QE 

747 

58 
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DOCUMENTS 
DEPT. 


UC-NRLF 


ants 


U.  S.  GEOGRAPHICAL  AND  GEOLOGICAL  SURVEY  OP  THE  ROCKY  MOL\T\L\  REGION. 

J.     W.    FOWELL,    IN    CHARGKE. 


PRELIMINARY  REPORT 


OX  THE 


PALEONTOLOGY  OF  THE  BLACK  HILLS, 


K.    P.    WHITFIELD, 


CONTAINING  DESCRIPTIONS  OF  NEW  SPECIES  OF  FOSSILS  FROM  THE 

POTSDAM,  JURASSIC,  AND  CRETACEOUS  FORMATIONS  | 

OF  THE  BLACK  HILLS  OF  DAKOTA. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 
July,  T877. 


S.  GEOGRAPHICAL  AND  GEOLOGICAL  SURVEY  OF  THE  ROC1Y  MOUNTAIN  REGION. 

J.    W.    FO^VELL,    IN    CHARGJ-H5. 


PRELIMINARY  REPORT 


OX   THE 


PALEONTOLOGY  OF  THE  BLACK  HILLS, 


BY 


R. 


CONTAINING  DESCRIPTIONS  OF  NEW  SPECIES  OF  FOSSILS  FROM  THE 

POTSDAM,  JURASSIC,  AND  CRETACEOUS  FORMATIONS 

OF  THE  BLACK  HILLS  OF  DAKOTA. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

July,  1877. 


NOTE. 


The  new  species  of  fossils  described  in  this  preliminary  report,  by 
Professor  E.  P.  Whitfield,  from  the  Potsdam,  Jurassic,  and  Cretaceous 
formations,  are  such  forms  as  are  new  to  science  in  the  collections  made 
by  W.  P.  Jenney  and  H.  Newton  during  the  exploration  of  the  Black 
Hlls  of  Dakota  in  the  summer  of  1875. 

These  forms,  with  many  others  from  the  same  formations,  are  em- 
bodied in  the  final  report  on  the  paleontology  of  this  region,  which, 
with  sixteen  lithographic  plates,  will  accompany  the  publication  of  the 
final  results  of  the  exploration  in  the  Black  Hills. 

July,  1877. 


DOCUMENT 
DEPT. 


PRELIMINARY  REMARKS. 


The  species  described  in  the  followiDg  pages  were  collected  in  and 
around  the  Black  Hills  during  the  expedition,  and  represent  the  differ- 
ent formations  recognized,  except  the  Carboniferous,  from  which  the 
fossils  obtained  were  few  and  of  little  interest. 

The  horizon  of  the  Potsdam  formation  of  the  Black  Hills  appears  to 
be,  so  far  as  the  fossils  will  serve  to  determine,  about  the  same  as  that 
of  Wisconsin  and  the  neighboring  States ;  and  of  some  of  the  layers 
the  lithological  features  are  so  nearly  the  same  that  it  would  be  difficult 
to  distinguish  between  specimens  from  the  two  localities.  The  purplish- 
green  quartzitic  rock  from  the  head  of  Red  Caiion  Creek,  containing 
Lingulepis  pinniformis  Owen  sp.  and  several  other  Brachiopodous  shells, 
appears  to  hold  nearly  the  same  relation  to  the  rest  of  the  group  as 
does  that  at  the  Falls  of  the  St.  Croix,  from  which  the  species  was  orig- 
inally described,  namely,  near  the  base ;  the  Eed  Caiion  Creek  beds 
resting  immediately  on  the  slates  of  older  date  (probably  Huronian) 
while  the  Trilobitic  beds  and  the  soft  friable  layers  occur  at  a  horizon 
of  about  100  feet  below  the  Carboniferous.  The  entire  fauna  of  the 
Black  Hills  beds  closely  resembles  that  from  Wisconsin ;  although  the 
species  are  nearly  all  distinct,  the  generic  facies  is  the  same  through- 
out. Among  the  fossils  from  the  higher  parts  of  the  formation  there 
are  quantities  of  Plant  remains  belonging  to  the  genus  Palceophycus 
which,  I  am  informed,  cover  the  surface  of  the  rocks  over  large  areas 
where  exposed,  being  densely  matted  together.  These  beds  also  hold  a 
position  similar  to  the  Plant  beds  of  other  localities. 

The  Jurassic  formations  seem  also  to  be  well  represented  in  this  region, 
'and  many  of  the  beds  are  highly  fossil  if ero  us.  The  species  are  not 
numerous,  but  the  individuals  are  extremely  abundant,  many  of  the 
slaty  calcareous  layers  being  so  largely  composed  of  organic  remains, 
mostly  Lamellibrauchiates,  as  to  be  quite  friable  and  easily  broken  in 
the  hand,  and  some  of  the  sandy  layers  have  their  surfaces  densely  cov- 
ered with  the  separated  shells  of  one  or  two  species.  The  absence  of 
Gasteropoda  is  a  noticeable  feature  at  all  localities  from  which  specimens 
have  been  brought,  no  example  of  this  class  of  molluscs  being  present 
in  the  entire  collections  from  this  formation.  The  few  species  of  Fresh- 
water Gasteropoda  described,  as  probably  from  this  horizon,  in  the 
Smithsonian  Contributions,  (Pal.  Up.  Missouri,)  being  still  doubtfully 
referred.  This  same  absence  of  Gasteropoda  is  also  noticed  in  all  the 
collections  of  Jurassic  age  we  have  seen  from  the  western  countries. 

3 


not  more  than  three  or  four  species  having  been  obtained  beyond  those 
above  referred  to. 

Among  the  Cretaceous  fossils  there  are  many  forms  of  great  interest, 
especially  among  the  Inocerami  and  Cephalopoda.  Among  the  former 
the  forms  described  under  the  new  generic  name  of  Endocostce  are  in- 
teresting as  affording  light  on  a  group  of  shells  that,  although  long 
known,  have  not  been  fully  understood,  probably  owing  to  the  want  of 
more  and  better  material  which  this  collection  has  afforded,  the  feature 
there  described  having  been  seen  on  isolated  specimens,  poorly  pre- 
served. 

Among  the  Cephalopods  of  the  Cretaceous  there  are  some  fine  exam- 
ples of  the  aberrant  forms  of  the  Ammonite  group,  which  show  very 
conclusively  that  a  rich  field  awaits  the  future  collector  in  this  region.  In 
some  of  the  localities  of  this  formation,  from  which  collections  have 
been  brought,  there  appears  to  be  a  difficulty  in  recognizing  the  divis- 
ions of  the  group,  proposed  by  Messrs.  Meek  and  Hayden,  as  the  fossils 
of  two  of  the  divisions  are  found  intermingling  at  the  same  place  and 
in  the  same  layers.  The  specimens  brought  from  the  locality,  on  Old 
Woman's  Fork  of  the  Cheyenne,  are  of  this  character,  and  there  seems 
to  be  the  same  trouble  among  those  from  certain  parts  of  Beaver  Creek. 
The  collection  affords  no  specimens  belonging  strictly  to  the  Divisions 
No.  1  and  No.  3,  though  the  beds  were  observed  but  not  collected  from. 


FOSSILS  FROM  THE  PRIMORDIAL  ROCKS. 


PLANTS. 

GENUS  PAL^EOCHOKDA. 

PALJEOCHORDA  PRIMA,  n.  sp. 

Plate  1,  fig.  2. 

Plants,  the  remains  of  which,  as  preserved  on  the  surface  of  the  rock, 
consist  of  narrow,  linear,  grass-like  stipes,  coiled  or  twisted  without 
any  regular  order,  leaving  by  their  removal  or  decomposition  flattened 
depressions  of  from  one  line  to  two  lines  in  width  and  of  an  indefinite 
length,  with  rounded  or  obtusely- pointed  extremities. 

The  examples  in  the  collection  before  us  are  coiled,  forming  irregular 
curves,  usually  enrolled,  but  sometimes  sigmoidal.  The  surfaces  are 
smooth  and  structureless,  presenting  no  marking  whatever,  although 
the  substance  is  usually  of  a  somewhat  lighter  color  than  the  surround- 
ing rock.  The  terminations  are  usually  sharply  rounded,  and  the  whole 
appearance  is  more  that  of  the  impression  of  an  Annelid  than  of  a  plant, 
though  it  is  difficult  to  conceive  of  the  preservation  of  anything  other 
than  a  plant  to  leave  such  markings.  We  have  referred  them  to  the 
above  genus,  presuming  them  to  be  congeneric  with  those  figured  by 
Professor  McCoy  in  his  Synopsis  British  Palaeozoic  Fossils,  plate  1  A, 
fig.  3,  although  they  are  not  elevated  or  rounded  bodies,  but  flattened 
stipes. 

Formation  and  locality. — In  the  plant  beds  of  the  Potsdam  formation 
(probably  Upper  Potsdam  or  Calciferous),  Head  of  Red  Water  Valley, 
Black  Hills,  Dakota. 

GENUS  PALJ]OPHYCUS,  Hall 

PAL^EOPHYCUS  OCCIDENTALS,  n.  sp. 

Plate  1,  fig.  3. 

Remains  consisting  of  strong,  subcylindrical,  flexuous  stems  or  roots, 
covering  the  surface  of  the  sandstone.  The  steins  are  more  or  less 
rounded,  although  frequently  quite  flattened,  and  varying  in  diameter 
from  one-fourth  of  an  inch  to  one  inch,  frequently  bifurcating  and  some- 
times dividing  into  threes.  They  are  commonly  interlaced  with  each 
other,  but  do  not  appear  to  coalesce,  but  are  simply  overlapped  5  the 
surfaces,  although  sometimes  quite  smooth,  are  generally  marked  by 
indistinct  longitudinal  pits  and  ridges  of  greater  or  less  extent,  fre- 

7 


quently  occurring  of  an  inch  in  length,  while  many  are  merely  short, 
roughened  depressions,  which  give  a  corrugated  surface  to  the  sterns. 

Judging  from  the  specimens  in  the  collection,  we  should  suppose  they 
often  attain  considerable  length,  as  on  a  specimen  measuring  nearly  ten 
inches  the  variation  in  diameter  is  scarcely  perceptible,  but  occasion- 
ally one  will  be  found  to  terminate  in  an  obtuse  point. 

This  species  bears  some  resemblance  to  Fucoides  duplex  Hall,  (Post.  & 
Whit.,  Lake  Sup.,  p.  226,  pi.  A.,  23,  fig.  1,)  but  does  not  present  the 
longitudinal  depression  along  the  middle  as  in  that  one,  except  near  a 
bifurcation.  It  is  very  similar  to  P.  tubularis  Hall,. from  the  Calciferous 
Sandstone  of  Ke\y  York ;  but  is  less  ridged  and  has  a  somewhat  differ- 
ent mode  of  bifurcation  from  any  of  the  specimens  of  that  species  which 
we  have  seen.  If  a  larger  number  of  the  New  York  species  were  ex- 
amined, however,  it  is  possible  that  the  resemblance  might  be  much 
greater  than  at  present  supposed. 

Formation  and  locality. — In  the  plant  beds  of  the  Potsdam  formation 
(probably  Upper  Potsdam  or  Calciferous).  Head  of  Bed  Water  Valley, 
Black  Hills,  Dakota. 

MOLLUSCOIDA. 

BRACHIOPODA. 

LlNGULEPIS  CUNEOL.US,  n.  sp. 
Plate  2,  figs.  5  and  6. 

Shells  small,  rather  below  the  medium  size,  triangularly  ovate  in  out" 
line,  or  sometimes  subcuneate ;  ventral  valve  triangularly  ovate,  with 
a  sharp  somewhat  pointed  beak,  the  width  and  length  about  as  three 
and  four,  and  the  point  of  greatest  length  near  the  lower  third  of  the 
length  of  the  valve;  cardinal  slopes  abrupt,  scarcely  convex;  basal  line 
rounded  at  the  sides  but  nearly  straight  in  the  middle  ;  surface  of  the 
valve  strongly  convex,  becoming  almost  subangular  in  the  upper  part 
dorsal  valve  much  shorter,  proportionally,  than  the  ventral,  the  length 
but  little  exceeding  the  width ;  sides  and  base  more  rounded  and  the 
beak  truncate ;  surface  distinctly  convex. 

Surface  of  the  shell  apparently  smooth,  but  usually  exfoliated,  in 
which  condition  a  few  fine  radiating  lines  are  visible. 

The  shell  differs  from  L.  pinnaformis  Ovven,  in  size  and  in  the  more 
distinctly  cuneate  form  of  the  ventral  valve.  At  first  sight,  it  might  be 
taken  for  the  young  of  that  species,  but  a  little  critical  examination 
soon  reveals  marked  distinctions  in  the  truncation  of  the  front  margin, 
and  especially  in  the  form  of  the  cardinal  slopes,  which  are  rounded 
and  never  concave,  as  in  almost  all  ventral  valves  of  that  species.  In  con- 
sequence of  this  latter  feature,  the  beak  does  not  appear  so  attenuated 
as  in  that  one,  although  proportionally  quite  as  long.  In  the  general 


surface  characters  and  form  of  the  valves  it  corresponds  with  the  genus 
Linyulcpis,  although  we  have  not  been  able  to  distinguish  the  muscular 
impressions. 

Were  it  not  for  the  difference  in  the  size  of  the  shells,  we  should  be  in- 
clined to  think  this  might  be  the  species  figured  by  Messrs.  Meek  and 
Haydeu,  (Pal.  Upp.  Missouri,  p.  3,  PI.  1,  fig.  1  a  and  &,)  as£.  Dakotensis; 
but  as  their  figures  appear  to  be  of  the  natural  size,  we  should  suppose 
it  to  be  very  distinct,  as  all  the  specimens  of  our  shell  noticed  have 
been  small,  none  exceeding  one-fourth  of  an  inch  in  length. 

Formation  andloeality. — In  soft,  friable  sandstone  of  the  Potsdam  group, 
at  Red  Canon  Creek,  in  the  Southwest  Black  Hills,  Dakota. 

LTNGULEPIS  PERATTENUATUS,  n.  si). 

Plate  2,  figs.  7-9. 

Shell  spatulate  or  elongate-ovate,  becoming  acutely  pointed  toward 
the  beak;  sides  below  the  middle  of  the  length  of  the  ventral  valve, 
rounded ;  front  margin  very  regularly  curved ;  cardinal  slopes  straight, 
or  sometimes  slightly  convex,  greatest  width  a  little  more  than  half  the 
length  of  the  ventral  valve  and  sometimes  nearly  two-thirds  as  great. 
Surface  of  the  ventral  valve  depressed  convex,  very  slightly  subangular 
along  the  middle  above  the  lower  third  of  the  length,  and  a  little  more 
distinctly  so  in  the  upper  part.  Apex  scarcely  truncate.  Dorsal  valve 
considerably  shorter  than  the  ventral,  broadly  truncated  at  the  upper 
end,  the  line  of  truncation  being  distinctly  arched.  Surface  evenly  con  - 
vex.  Structure  of  the  surface  of  the  shell  polished,  with  fine,  somewhat 
lamellose,  lines  of  growth. 

The  shell  in  many  points  closely  resembles  L.  pinnaformis  Owen,  but 
is  a  proportionally  longer  shell  and  not  exceeding  one-half  the  size  of 
the  adult  specimens  of  that  species.  When  compared  in  shape,  it  is 
more  elongate  in  front,  the  lower  end  of  the  shell  forming  a  section  of 
an  ellipse  rather  than  of  a  circle  as  in  that  one;  the  cardinal  slopes  are 
convex  and  the  valves  proportionally  longer,  the  apex  being  more  elon- 
gated in  proportion  to  the  size  of  the  body  of  the  shell,  but  not  so  nar- 
row. The  two  species  are  associated  in  the  same  blocks,  and  the  dis- 
similarity between  examples  of  the  same  size  is  so  perceptible  that  there 
will  not  be  the  slightest  difficulty  in  recognizing  them  as  distinct. 

Formation  and  locality. — In  greenish-purple  sandstone  of  the  Potsdam 
formation,  at  the  Headwaters  of  Red  Cafion  Creek,  southwest  Black 
Hills,  Dakota. 


10 

ARTICULATA. 

TKILOBITA. 

CALYMENnm 

GENUS  CREPICEPHALUS,  Owen  (?LOGANELLUS,  D 
CREPICEPHALUS  (LOGANELLUS)  CENTRALIS,  n.  s}). 

Plate  2,  figs.  21-24. 

Species  recognized  only  by  the  glabella  and  fixed  cheeks,  with  a  few 
imperfect  fragments  of  the  movable  cheeks.  The  former  parts,  when 
united,  are  somewhat  quadrangular  in  outline,  broadest  at  the  base  and 
gently  narrowing  in  front  ;  glabella  rounded-conical,  higher  than  wide, 
the  anterior  end  somewhat  sharply  rounded ;  surface  highly  convex  and 
marked  by  three  pairs  of  distinct  lateral  furrows,  which  are  strongly 
bent  backward  in  their  direction  from  the  margin,  and  on  the  larger 
specimens  the  posterior  pair  almost  unite  in  the  middle.  Occipital  fur- 
row distinct,  extending  entirely  across  the  base  of  the  head  ;  occipital 
ring  strong,  rounded,  and  in  the  older  individuals  supporting  a  short 
spine;  dorsal  furrows  well  pronounced,  extending  with  equal  clearness 
in  front  of  the  glabella.  Fixed  cheeks  broad,  more  than  equaling  one- 
half  the  width  of  the  glabella;  palpebral  lobes  small  and  slightly  angu- 
lar, situated  opposite  the  middle  of  the  glabella;  ocular  ridges  distinct, 
directed  anteriorly  in  passing  from  the  eye  to  the  dorsal  furrow.  Frontal 
limb  short,  not  more  than  one-third  as  long  as  the  glabella,  one-half  of 
its  length  formed  by  the  strong,  rounded  marginal  rim  and  furrow. 
Facial  suture  directed  gently  inward  from,  the  front  of  the  eye  lobe  to 
the  anterior  margin,  with  but  little  curvature;  behind  the  eye  it  is 
•directed  backward  and  outward  at  an  angle  of  from  thirty-five  to  forty 
degrees  with  the  occipital  line  of  the  head,  with  a  slightly  sigmoidal 
curvature,  giving  an  elongate  triangular  form  to  the  postero-lateral 
limbs. 

There  is  considerable  variation  in  the  form  and  proportions  of  the 
glabella  among  the  different  individuals  in  the  collection,  the  larger 
specimens  being  proportionally  broader  and  the  lateral  furrows  much 
more  distinctly  marked.  On  the  smaller  one  figured  the  furrows  are 
not  distinct  enough  to  indicate  without  exaggeration.  The  presence  or 
absence  of  an  occipital  spine  is  also  noticed,  dependent  apparently  on 
the  same  cause.  It  is  possible  that  the  two  individuals  may  belong  to 
different  species,  but  from  their  great  similarity  in  other  respects  we 
feel  confident  that  this  is  not  the  case. 

This  species  resembles  in  some  of  its  characters  C.  (Batkyurus  ?)  an- 
gulatus,  H.  &  W.,  from  the  same  formation  on  the  west  side  of  Pogonip 
Mountain,  White  Pine,  Nev.,  described  in  Mr.  Clarence  King's  report, 
but  lacks  the  angular  frontal  limb  of  that  species,  and  the  facial  sutures 


11 

converge  in  front  of  the  eye,  while  in  that  one  they  are  slightly  diverg- 
ent. We  know  of  no  other  species  with  which  it  is  closely  related, 
unless  it  should  prove  to  be  more  nearly  related  to  Agraulus  Oiceni, 
Meek  &  Hayden,  Pal.  Upp.  Missouri,  p.  9,  figs.  A,  B,  C,  than  we  are 
inclined  to  believe.  There  are  several  particulars  in  which  it  differs 
very  materially  from  their  figures,  and  also  from  the  description  given, 
that  would  at  once  mark  it  as  distinct,  if  it  were  not  that  the  imperfect 
material  in  both  cases  tends  to  lead  to  error.  The  difference  in  the 
width  of  the  occipital  lobe  is  a  very  marked  one,  and  also  the  length  of 
the  frontal  limb,  while  the  form  of  the  glabella  varies  much  in  being 
more  distinctly  conical  than  in  that  species. 

Formation  and  locality. — In  coarse  sandstones  of  the  Potsdam  forma- 
tion, at  Castle  Creek,  West  Black  Hills,  Dakota. 

CREPICEPHALUS  (LOGANELLUS)  PLAXUS,  n.  sp. 

Plate  2,  fig.  20. 

Glabella  and  fixed  cheeks,  when  united,  subquadrangular  in  outline, 
narrowest  across  the  eyes  and  slightly  expanding  in  front,  and  more 
abruptly  so  posteriorly.  Glabella  very  depressed  convex,  slightly 
conical  and  somewhat  squarely  truncate  in  front,  the  width  across  the 
base  being  equal  to  about  three-fourths  of  the  height  above  the  occipital 
furrow,  and  that  of  the  anterior  end  to  about  half  the  height  j  lateral 
furrows  very  faintly  marked,  oblique,  and  extending  about  one-third  of 
the  width  from  the  margin.  Occipital  furrows  not  strongly  marked, 
extending  entirely  across  the  base  of  the  head ;  ring  narrow,  and  with- 
out spine.  Dorsal  furrows  distinct,  but  not  deep,  extending  around 
the  front  of  the  glabella.  Fixed  cheeks  wide,  more  than  half  as  wide, 
opposite  the  eyes,  as  the  middle  of  the  glabella.  Frontal  limb  of  moder- 
ate length,  at  least  as  long  as  the  width  of  the  anterior  end  of  the  gla- 
bella, but  its  entire  extent  and  anterior  margin  have  not  been  fully  ascer- 
tained. Facial  suture  cutting  the  anterior  border  at  right  angles  to  the 
margin  of  the  head  and  directed  slightly  inward  to  the  eyes,  behind  which 
it  is  directed  obliquely  backward,  at  an  angle  of  about  60°  with  the  base 
of  the  head,  to  the  occipital  furrow,  behind  which  it  runs  more  directly 
outward.  Ocular  ridges  distinct.  Palpebral  lobes  small  and  situated 
behind  the  middle  of  the  head. 

The  species  is  only  known  by  the  glabella  and  fixed  cheeks,  and  is 
remarkable  only  for  its  general  flatness  and  want  of  prominent  charac- 
ters. There  is  no  known  species  from  the  same  formation  either  in  the 
Wisconsin  locality  or  from  the  more  western  regions  that  is  so  closely 
related  to  it  as  to  be  readily  mistaken.  <?.  (L.)  quadra-vis,  H.  &  W., 
of  Clarence  King's  report,  from  the  slates  above  Call's  Fort,  North 
Wahsatach  Mountains,  is  perhaps  as  closely  related  as  any,  but  differs 
in  having  the  glabella  more  rounded  in  front  and  proportionally  broader. 

Formation  and  locality. — Associated  in  the  same  beds  and  locality 
with  the  preceding  species. 


FOSSILS  FROM  THE  JURASSIC  ROCKS. 


13 


RADIATA. 

ECHINODERMATA. 

ASTEROIDEA. 

GENUS  ASTERIAS,  Linneus. 

ASTERIAS  ?DUBHJ3I,  n.  Sp. 

Plate  3,  fig.  3. 

Several  impressions  of  a  species  of  star-fish,  apparently  of  the  genus 
Asterias,  are  present  in  the  collection  from  a  bed  of  light-red  sandstone, 
which  occurs  at  a  horizon  of  from  80  to  100  feet  above  the  Triassic  red 
beds. 

The  specimens  are  not  in  a  condition  to  afford  a  full  description  of 
their  specific  characters.  They  are  of  small  size,  the  rays  being  from 
three-fourths  of  an  inch  to  one  and  one-fourth  inches  long,  measuring 
from  the  center  of  the  body.  The  rays  are  slender  and  flexuous,  most 
of  them  being  more  or  less  curved  in  their  direction  and  elevated  along 
the  middle,  as  shown  on  a  gutta-percha  cast  taken  in  a  natural  mold  of 
a  group  of  three  individuals.  The  upper  surface  is  subangular,  and  in 
structure  they  are  apparently  composed  of  small  nodiform  plates,  placed 
in  longitudinal  rows.  The  center  of  the  body  or  disk  is  marked  by  an 
obscurely  pentangular  depression  on  the  upper  surface.  None  of  the 
specimens  show  the  under  side  of  the  body  or  rays,  so  that  the  charac- 
ters of  these  parts  are  entirely  unknown. 

The  species  appears  to  have  been  some.what  abundant,  judging  from 
the  condition  in  which  they  are  grouped  on  the  sandstone,  and  although 
the  specimens  are  obscure  and  too  imperfect  for  positive  determination 
and  description,  it  has  been  thought  best  to  designate  them  by  name, 
as  they  will  undoubtedly  prove  a  characteristic  form  over  a  certain 
region,  and  of  a  limited  horizon.  The  sandstone  is  marked,  on  the 
layers  in  which  they  are  found,  by  ripple  or  wave  marks,  having  a 
width  of  about  3  inches,  and  indicates  a  near  proximity  to  a  shore-line 
over  the  area  where  they  were  obtained,  and  that  the  individuals  are 
probably  stranded  specimens.  A  single  very  imperfect  impression  of  a 
Lamellibranchiate  shell  is  represented  on  the  same  fragments  of  rock, 
but  too  imperfect  for  determination. 

Formation  and  locality. — In  red  sandstones  of  Jurassic  age,  Park 
Sands,  70  feet  above  the  red  beds,  on  the  east  side  of  Spear-Fish  Creek, 
near  its  junction  with  the  Bed  Water,  northeast  of  Crow  Peak,  Black 
Hills,  Dakota. 

15 


16 

PECTENIDJE. 

GENUS  PECTEN,  Brug. 
PECTEN  NEWBERRYI,  n.  sp. 

Plate  4,  figs.  12-15. 

Shell  of  moderate  size,  suborbicular  in  outline,  erect  and  subequilat- 
<eral,  the  height  and  length  nearly  equal.  Valves  depressed-lenticular 
in  a  transverse  section  when  united ;  their  surfaces  depressed- con  vex, 
except  along  the  sides  of  the  valves  near  the  cardinal  slopes,  where  the 
surface  is  elevated  so  as  to  form  a  broad,  rounded,  fold-like  border  on 
this  part ;  with  a  broad,  undefined,  shallow  depression  separating  it 
from  the  body  of  the  valve.  Hinge  line  short;  that  of  the  left  valve 
less  than  half  as  long  as  the  shell  below  ;  straight  or  a  very  little  slop- 
ing outward  from  the  apex  of  the  valve,  which  is  small,  appressed,  and 
not  projecting  above  the  line  of  the  hinge.  Anterior  side  of  the  hinge 
a  little  longer  than  the  other,  the  anterior  wing  being  rounded  at  the 
extremity,  more  than  as  long  again  as  the  height  above  the  body  of  the 
valve  at  its  widest  part ;  separated  from  the  shell  below  by  a  very  shal- 
low, rounded  byssal  notch,  and  along  the  surface  by  a  scarcely  percepti- 
ble groove  bordering  the  body  of  the  valve.  Posterior  wing  smaller, 
triangular,  a  little  obtuse  at  the  outer  upper  angle,  and  proportionally 
somewhat  higher  or  longer  on  the  lateral  border  than  the  anterior  wing. 
Surface  of  the  left  valve  marked,  except  on  the  fold  and  depression 
bordering  the  cardinal  slopes,  by  strong,  flattened  radii,  which  are  vari- 
able in  strength,  size,  and  distance,  and  are  separated  by  flattened 
interspaces,  usually  of  greater  width  than  the  ribs  themselves.  The 
surface  is  also  marked  by  closely  arranged,  distinctly  elevated,  regular, 
lamellose,  concentric  lines  parallel  to  the  outer  margin,  and  coincident 
with  the  lines  of  growth,  and  are  slightly  arched  backward  in  crossing 
the  radii.  These  latter  markings  also  cover  the  surface  of  the  folds  of 
the  cardinal  borders  and  the  cardinal  auriculations. 

A  single  right  valve  of  small  size  associated  with  a  number  of  left 
valves,  on  the  same  block,  has  the  same  general  form  and  the  same 
fold-like  feature  of  the  cardinal  slopes,  but  appears  to  be  entirely  desti- 
tute of  the  radii  on  the  body  of  the  valve ;  and  the  concentric  markings 
are  also  much  less  distinct  and  regular  than  on  the  opposite  valve.  The 
anterior  wing  is  also  very  small  and  obtusely  triangular,  but  may  have 
been  somewhat  mutilated.  There  can  be  little  if  any  doubt,  however, 
that  this  right  valve  belongs  to  the  same  species. 

This  species  may  be  readily  distinguished  by  the  peculiar  fold  like 
feature  of  the  cardinal  slopes  and  the  character  of  the  concentric  mark- 
ings, being  entirely  different  in  these  respects  from  any  other  of  the 
genus  described  from  rocks  of  this  age. 


17 

Formation  and  locality. — In  reddish  and  buff  colored   argillaceous 

limestones  of  Jurassic  age,  at  T Spring,  west  of  the  Black  Hills 

of  Dakota. 

PSEUDOMONOTIS  (EUMICROTIS)   ORBICULATA,   11.  sp. 
Plate  3,  figs.  17-19. 

Shell  of  moderate  size,  orbicular  in  outline,  nearly  equilateral  and 
subdiscoid.  Left  valve  depressed-convex,  most  rotund  just  below  and 
anterior  to  the  beak ;  beak  small,  full,  slightly  incurved,  and  projecting 
somewhat  above  the  cardinal  border.  Anterior  wing  very  short,  almost 
obsolete,  the  anterior  end  regularly  rounded  from  its  extremity  to  and 
along  the  basal  margin ;  posterior  wing  of  moderate  size  and  com. 
pressed,  shorter  than  the  shell  below,  the  posterior  margin  rounding 
backward  from  its  extremity  to  near  the  middle  of  the  length  of  the 
valve,  thence  somewhat  regularly  rounded  to  the  base.  Surface  of  the 
valve  marked  by  numerous  unequal,  slender,  and  slightly  elevated  radii, 
which  are  separated  by  wider  flattened  interspaces ;  also  by  irregular 
concentric  stride  of  growth,  which  often  give  a  knotty  or  roughened  sur- 
face to  the  radii  where  crossing  them,  especially  toward  the  posterior 
border  and  near  the  outer  margin.  Eight  valve  less  convex  than  the 
opposite  one,  with  a  smaller  inconspicuous  beak,  which  does  not  project 
beyond  the  cardinal  line.  Anterior  side  of  the  hinge  line  characterized 
by  a  small  and  very  obscure  wing,  which  is  reduced  to  a  mere  point, 
reaching  to  not  more  than  one-third  of  the  length  of  the  very  short  an- 
terior side  of  the  hinge.  The  wing  is  separated  from  the  body  of  the 
shell  below,  as  in  others  of  this  division  of  the  group,  by  a  narrow  and 
rather  deep  groove,  but  not  by  a  distinct  sinus.  Posterior  wing  longer 
and  compressed,  but  not  extending  to  more  than  half  the  length  of  the 
body  of  the  shell  below.  Surface  of  the  valve  marked,  in  all  cases  ob- 
served, by  fainter  radii  than  the  left  valve,  but  otherwise  of  similar 
character. 

This  species  is  closely  related  to  P.  (E.}  curta,  Hall,  but  is  much  larger, 
several  of  the  individuals  measuring  seven-eighths  of  an  inch  in  length, 
and  one  specimen  measures  nearly  an  inch ;  while  those  of  that  species 
seldom  attain  to  more  than  two-thirds  of  that  size.  The  shell  is  also 
much  less  oblique;  less  convex;  the  radii  sharper  and  not  usually  so 
distant,  although  in  this  latter  feature  they  both  differ  very  materially 
among  the  different  individuals,  and  the  right  valve  is  also  distinctly 
marked  by  the  radii,  which  is  not  the  case  in  that  one. 

Formation  and  locality. — In  calcareous  clays  of  Jurassic  age,  ranging 
about  20  feet  above  the  red  beds,  at  Red  Water  Valley,  Black  Hills, 
Dakota. 

2  B  H 


18 

FAM.  MYTILDXffi. 

GENUS  MYTILUS,  Li  An. 

MYTILUS  WHITEI,  n.  sp. 

Plate  5,  figs.  9-12. 


Shell  of  moderate  size,  trapezoidal  in.  outline,  very  oblique;  hinge 
line  slightly  arcuate,  as  long  or  a  little  longer  than  the  distance  from 
the  apex  to  the  postero-basal  extremity ;  anterior  or  byssal  border  long, 
distinctly  concave  from  the  apex  of  the  beak  to  the  junction  of  the  basal 
border,  the  general  direction  being  at  an  angle  of  about  45°,  or  within 
45°  with  the  cardinal  line ;  posterior  margin  a  little  more  than  half  as 
long  as  the  shell  and  nearly  parallel  to  the  anterior  border,  or  slightly 
converging  toward  the  base ;  basal  margin  short  and  more  or  less 
rounded,  somewhat  variable  in  different  individuals.  Beaks  small, 
pointed,  terminal  and  incurved,  with  a  short  but  distinct  area-like 
space  beneath  them;  umbones  prominent,  subangular,  and  with  a 
slightly  flattened  or  concave  space  on  the  anterior  side,  just  below  the 
apex  of  the  beak.  Umbonal  ridge  elevated,  strongly  arcuate  and  sub- 
angular,  the  -surface  of  the  shell  sloping  rapidly  to  the  posterior  and 
postero-cardinal  margins.  Anterior  slope  of  the  shell  nearly  or  quite 
vertical,  or  sometimes  a  little  concave  near  the  middle  of  the  length. 

Surface  of  the  shell  marked  by  numerous  strong  but  very  irregular 
varices  of  growth,  which  give  to  the  shell  an  extremely  rugose  appear- 
ance. Bet  ween  the  varices  the  surface  is  marked  by  fine  lines  of  growth. 
No  radiating  lines  or  other  surface  markings,  beyond  those  described, 
can  be  detected.  Substance  of  the  shell  thick  and  strong. 

The  shell  is  a  strongly  marked  and  very  characteristic  species,  and 
judging  from  the  fragments  in  the  hand  specimens  of  rock,  must  have 
been  an  abundant  form  in  a  certain  layer  at  the  locality  where  collected. 
We  know  of  no  American  species  of  the  genus  having  any  close  resem- 
blance to  this  one. 

Formation  and  locality. — In  rocks  of  Jurassic  age,  associated  with 
other  Jurassic  fossils,  near  Sun-Dance  Hills,  Northwestern  Black  Hills, 
Wyoming. 

GENUS   TRAPEZIUM,  Humph.  (=  CYPRICARDIA,  Lam.}. 
TRAPEZIUM  BELLEFOURCHENSIS,  n.  sp . 

Plate  5,  figs.  1-4. 

Shell  small,  transversely  elongate-quadrangular,  the  length  being 
from  two  and  a  half  to  three  times  greater  than  the  height ;  dorsal  and 
basal  margin  subparallel,  the  former  very  slightly  arched  and  the  latter 
scarcely  concave,  except  in  the  older  individuals,  the  smaller  and  me- 


19 

(Hum-sized  individuals  being  usually  a  little  curved  upward  toward  the 
posterior  end;  beaks  small,  nearly  terminal,  rounded  on  the  umbones 
and  very  slightly  incurved;  posterior  extremity  truncate,  in  the  older 
specimens  rather  squarely  so  below,  and  rounding  forward  to  the  extrem- 
ity of  the  hinge-line  above.  In  the  smaller  individuals  it  is  narrower, 
somewhat  sloping  from  above  or  obliquely  truncate.  Anterior  end  very 
slightly  prolonged  below  the  middle  of  the  height  and  excavated  beneath 
the  beaks.  A  narrow  linear  escutcheon  of  considerable  length  is  seen  on 
many  of  the  separated  valves.  Anterior  muscular  impression  rather 
large  and  strongly  impressed,  as  shown  by  the  strong  markings  on 
internal  casts;  posterior  impression  not  distinguishable;  pallia!  line 
faint,  and  the  space  within  the  limits  often  marked  by  radiating  lines  as 
in  the  recent  forms  of  the  genus. 

Surface  of  the  valves  veutricose,  with  a  distinctly  angular  umbonal 
slope  in  the  larger  specimen,  but  often  obtusely  rounded  in  the  smaller 
ones.  A  broad  but  rather  faint  depression  runs  obliquely  backward 
from  the  beak  to  the  middle  of  the  basal  border  on  many  individuals, 
but  is  not  always  present.  Surface  of  the  shell  marked  by  irregular 
concentric  lines  of  growth  parallel  to  the  margin  of  the  valve. 

The  species  is  closely  allied  to  a  form  described  by  Mr.  Meek  (in  MS.) 
under  the  name  of  Trepezium  (Pachyniya)  truncata,  but  is  proportionally 
very  much  more  elongated  than  the  specimens  which  are  so  labeled  in 
the  collection  at  the  Smithsonian  Institution.  The  shells  have  been 
exceedingly  abundant  in  certain  layers,  being  densely  packed  together, 
so  that  it  is  impossible  to  separate  the  individuals.  They  are  quite  vari- 
able in  form  at  different  stages  of  growth,  the  younger  shells  being 
transversely  elongate-ovate,  narrowed  and  rounded,  or  very  obliquely 
truncate  from  above  posteriorly,  and  becoming  almost  squarely  truncate 
behind  in  the  older  specimens,  the  slight  sinuosity  of  the  basal  margin 
being  hardly  noticeable  until  they  attain  to  near  their  adult  size. 

Formation  and  locality. — In  a  hard  and  somewhat  siliceous  limestone  of 
reddish  color,  at  a  level  of  350  feet  above  the  Triassic  beds  east  of  Belle 
Fourche,  Black  Hills,  Dakota. 

TRAPEZIUM  SUBEQUALIS,  n.  sp. 

Plate  5,  figs.  5-8. 

Shell  small,  transversely  elougate-subelliptical,  about  twice  and  a  half 
as  long  as  high,  or  nearly  so.  Valves  somewhat  ventricose,  wi:h  large 
tumid  beaks  situated  a  little  nearest  to  the  anterior  end,  and  projecting 
above  the  general  line  of  the  hinge;  hinge-line,  posterior  to  the  beaks, 
about  half  as  long  as  the  entire  length  of  the  shell,  straight,  but  gradu- 
ally declining  to  the  extremity ;  posterior  end  of  the  shell  very  obliquely 
truncate,  being  much  the  longest  below  the  middle  of  the  postero-basal 
angle ;  anterior  end  shorter,  slightly  contracted  in  front  of  the  beaks, 
but  rounded  at  the  extremity  and  broader  than  the  opposite  end ;  basal 


20 

margin  straight  or  very  slightly  convex  in  the  middle,  and  strongly 
rounded  upward  toward  each  extremity.  Body  of  the  shell  often  dis- 
tinctly angular  along  the  posterior-umbonal  ridge  and  the  postero-cardi- 
nal  slope  quite  abrupt ;  some  individuals,  however,  are  obtusely  rounded 
on  the'umbonal  ridge.  Surface  of  the  shell  marked  by  rather  strong 
concentric  ridges  of  growth,  which  are  crossed,  on  the  rounded  anterior 
end  and  middle  of  the  valve,  by  extremely  fine  radiating  stripe,  only 
detected  near  the  basal  portion  of  the  larger  individuals  by  the  aid  of  a 
moderate  magnifying  power. 

There  may  be  some  little  doubt  as  to  the  true  generic  relations  of  this 
shell,  but  it  possesses  so  many  of  the  features  of  Trapezium  that  we  have 
not  hesitated  to  refer  it  to  that  genus ;  the  almost  subcentral  and  some- 
what prominent  beak  forms  the  strongest  point  of  difference.  It  differs 
in  this  respect  from  th  e  preceding  species,  as  also  in  the  general  form 
of  the  valves,  and  in  the  surface  markings.  The  shells  of  the  two 
species  have  nearly  the  same  dimensions,  and  in  their  mutilated  and 
imperfect  condition,  as  seen  imbedded  in  the  rock,  may  readily  be  con- 
founded, but  the  more  prominent  beaks  and  longer  anterior  end  of  this 
one  will  at  once  distinguish  them. 

Formation  and  locality. — In  a  hard  white  sandstone  of  Jurassic  age, 
associated  with  Pseudmonotis  curta  just  above  the  Triassic  red  beds,  at 
Bed  Canon  Creek,  Black  Hills,  Dakota. 

Family  uncertain.* 

GENUS  PLEUROMYA,  Agassi*. 
PLEUROMYA  NEWTONI. 

Plate  5,  figs.  19  and  20. 

Shell  of  moderate  size,  transversely  subovate  or  triangularly  ovate, 
the  greatest  height  being  across  the  valve  nearly  on  a  line  with  the 
beaks.  Valves  strongly  convex  near  the  anterior  end,  and  in  a  cardi- 
nal view  acutely  wedge-shaped,  thickest  opposite  the  beaks  and  rapidly 
decreasing  posteriorly.  Beaks  large,  strong,  enrolled,  and  approxi- 
mate, situated  at,  or  within,  the  anterior  third  of  the  shell  and  project- 
ing largely  above  the  the  cardinal  line.  Hinge-line  not  exceeding  one- 
half  the  length  of  the  shell,  distinctly  arched  ;  anterior  end  obliquely 
subtruucate,  longest  below  at  its  junction  with  the  basal  margin,  and 
in  some  cases  the  anterior  slope  is  distinctly  flattened.  Posterior  end 

*  The  family  relations  of  this  shell,  as  well  as  some  others  herein  described,  are  not 
yet  satisfactorily  determined,  and  we  do  not  like  to  refer  them  to  a  family  to  which 
we  feel  certain,  from  their  characters,  as  far  as  known,  they  have  no  resemblance  or 
affinity ;  we  rather  prefer  to  leave  them  in  doubt,  and  as  subjects  for  future  investiga- 
tion. The  reference  of  Pleuromya  and  Myacites  to  the  same  family  with  Anaiina  we  deem 
unnatural,  as  from  the  character  of  the  shell,  and  the  consequent  habits  of  the  animal, 
they  must  have  been  very  far  removed  from  each  other  in  structural  features,  and 
these  we  deem  the  ny  sure  and  reliable  means  of  classification. 


21 

narrowed,  the  postero-cardinal  margin  rapidly  declining  from  the  ex- 
tremity of  the  hinge-line  to  the  longest  point  of  the  valve,  which  is 
narrowly  rounded  and  at  about  the  middle  of  the  height ;  basal  margin 
very  slightly  constricted,  or  emarginate,  just  within  the  anterior  third 
of  the  length,  by  a  faint  sulcus,  which  passes  from  the  surface  of  the 
umbo  to  the  base  of  the  shell ;  posterior  to  this  it  is  strongly  convex, 
and  as  it  approaches  the  posterior  third  of  the  length  is  more  strongly 
rounded  upward  to  the  extremity.  Body  of  the  valve  convex,  most 
ventricose  on  the  umboues  and  along  the  middle  of  the  valve ;  anterior 
umbonal  ridge  obtusely  angular;  anterior  slope  abrupt  and  sometimes 
flattened  obliquely ;  posterior  umbonal  ridge  scarcely  defined  or  broadly 
rounded.  Immediately  behind  the  anterior  umbonal  ridge  a  broad 
undefined  sulcus  passes  across  the  valve,  slightly  modifying  the  direction 
of  the  concentric  lines.  Xo  appearance  of  escutcheon  or  lunule  exists, 
nor  of  an  external  ligament. 

Surface  of  the  shell  marked  by  numerous  irregular  concentric  undu- 
lations, which  are  usually  broad  and  undefined,  but  on  some  individuals 
have  a  slightly  sharper  character.  The  general  surface  beyond  these 
undefined  undulations  appears  to  have  been  smooth,  and  we  should 
suppose  from  its  character  that  it  had  been  semipolished.  Substance 
of  the  shell  moderately  thick.  The  features  of  the  hinge  and  interior 
have  not  been  fully  ascertained ;  there  appears,  however,  on  a  left  valve 
a  strong  tooth-like  process  of  considerable  height,  and  in  front  of  it  a 
deep  triangular  pit,  probably  ligamental. 

This  species  differs  from  Myacites  (Pleuromya)  subcompressa,  Meek 
(Sixth  An.  Kept.  U.  S.  Geol.  Surv.  Territories,  1872,  p.  472),  in  being  pro- 
portionally longer ;  more  distinctly  ovate  or  less  triangular.  The  ante- 
rior end  being  of  greater  length  in  proportion  to  the  rest  of  the  valve, 
the  beaks  are  larger  and  project  farther  above  the  cardinal  line; 
the  body  of  the  shell  is  less  flattened  and  the  surface  less  strongly 
marked. 

Formation  and  locality. — In  shaly  limestone  of  Jurassic  age,  on  top  of 
the  highest  hills  two  miles  south  of  Belle  Fourche,  Black  Hills,  Dakota. 

TA^CREDIA  COEBULIFOMIS,  n.  sp. 

Plate  6,  figs.  5-8. 

Shell  small,  seldom  measuring  more  than  half  an  inch  in  length,  very 
broadly  ovate  in  outline  and  largest  on  the  posterior  side  of  the  beaks, 
the  length  being  a  little  more  than  once  and  a  half  the  height;  the  beaks 
large  and  full,  slightly  enrolled,  almost  central  and  strongly  inclined  to- 
ward the  anterior  part  of  the  shell.  Anterior  end  narrowed,  strongly 
constricted  in  front  of  the  beaks,  giving  a  somewhat  concave  antero- 
cardinal  line,  the  extremity  acutely  rounded;  posterior  end  broadly 
rounded,  and  the  postero  cardinal  line  convex  to  near  the  beaks ;  basal 
line  regularly  curved  except  at  the  posterior  part  where  it  becomes  a 


22 

little  more  abrupt.  Body  of  the  valve  strongly  convex,  almost  inflated 
on  the  urnbo. 

Surface  of  shell  apparently  smooth,  but  under  a  magnifier  showing 
faint,  scarcely  defined,  lines  of  growth. 

The  species  differs  from  T.  inornata,  M.  &  H.,  in  its  smaller  size,  more 
inflated  valves,  proportionally  larger  and  more  prominent  beaks,  and 
greater  inequality  in  size  of  the  anterior  and  posterior  parts  of  the 
shell. 

Formation  and  locality. — In  sandy  and  somewhat  shaly  limestones 
of  Jurassic  age,  350  feet  above  the  red  beds  of  the  Triassic,  east  of 
Belle  Fourche,  Black  Hills,  Dakota. 

TANCREDIA  BULBOSA,  n.  sp. 

Plate  6,  figs.  1-3. 

Shell  very  small,  the  larger  individuals  not  measuring  more  than  three- 
eighths  of  an  inch  in  length,  by  a  height  of  one-fourth  of  an  inch  ;  very 
broadly  ovate  in  outline,  being  inflated  and  globuliform  in  the  middle 
and  posteriorly,  and  attenuate,  narrowed  and  compressed  toward  the 
anterior  extremity.  Beak  strong,  inflated,  curving  anteriorly,  and  sit- 
uated a  little  to  the  anterior  of  the  middle  of  the  shell ;  anterior  end 
acutely  rounded,  the  sides  of  the  shell  abruptly  compressed  by  a  broad, 
undefined,  constricting  sulcus,  or  depression,  which  passes  obliquely 
across  the  valve  from  in  front  of  the  beaks  to  the  basal  border,  in 
which  it  forms  a  distinct  emargiuation ;  posterior  end  broadly  rounded, 
and  the  posterior  cardinal  line  strongly  convex;  antero-cardinal  line 
constricted  in  front  of  the  beaks,  and  concave  between  them  and  the 
anterior  extremity ;  basal  line  very  convex  for  a  little  more  than  two- 
thirds  of  the  length  from  the  posterior  end,  where  it  becomes  emargi- 
nate  at  the  base  of  the  oblique  sulcus  or  depression,  which  crosses  the 
anterior  part  of  the  valve.  Surface  semi-polished,  and  under  a  magni- 
fier showing  fine  lines  of  growth. 

The  species  resemble  T.  corbuliformis  herein  described,  but  is  a  smaller 
shell,  seldom  occurring  of  more  than  half  the  usual  length  of  that  one, 
and  is  much  more  extreme  in  the  unequal  size  of  the  anterior  and  pos- 
terior parts  of  the  valve,  besides  being  much  more  globose  in  form,  and 
having  the  anterior  oblique  sulcus  of  the  valve  much  more  strongly 
marked. 

Formation  and  locality. — In  rock  of  Jurassic  age  associated  with  T. 
corbuliformis  and  T.inornata  at  the  same  locality. 

TANCREDIA  POSTICA,  n.  sp. 

Plate  6,  fig.  14. 

Shell  small,  trausversly  ovate,  the  height  and  length  being  about  as 
three  to  five.  Valves  very  ventricose,  becoming  tumid  near  the  beaks 
and  on  the  postero-cardinal  part.  Beaks  large,  and  but  little  elevated 


23 

above  the  cardinal  line,  slightly  enrolled  and  directed  forward,  situated 
at  about  one-third  of  the  length  from  the  anterior  extremity;  antero- 
cardinal  line  abruptly  declining  in  front  of  ,  the  beaks  to  the  middle  of 
the  height  of  the  valve  ;  anterior  end  narrow  and  sharply  rounded  ; 
posterior  end  very  broadly  rounded,  and  the  postero-cardinal  and  basal 
margins  subparallel  behind  the  beaks,  the  extreme  height  of  the  shell 
continuing  to  the  posterior  end;  antero-basal  line  strongly  curving 
upward  to  the  anterior  end  of  the  shell.  Surface  of  the  valves  appar- 
ently smooth. 

The  shell  differs  from  any  of  the  preceding  species  in  the  greater 
length  and  proportionate  size  of  the  posterior  portions  of  the  shell,  in 
the  situation  of  the  beaks,  and  in  their  strong  anterior  inclination,  the 
others  being  much  more  erect  than  those  of  this  species.  It  will  be 
readily  recognized  by  the  inflated  valves,  subparallel  cardinal  and  basal 
margins,  and  short  anterior  end. 

Formation  and  locality.  —  In  shaly  limestones  of  the  Jurassic  formation 
east  of  Belle  Fourche,  Black  Hills,  Dakota,  associated  with  the  preced- 
ing species. 

FAM.  V 


GENUS  DOSINIA,  Scopoli. 

DOSINIA  JUEASSICA,  H.  sp. 
Plate  5,  figs.  21-24. 

Shell  of  moderate  size,  subcircular  or  very  slightly  transverse  in  form, 
and  for  the  genus  quite  ventricose,  with  rather  large,  prominent  beaks. 
Cardinal  line  arcuate  but  less  curved  than  the  general  circle  of  the 
shell,  while  the  anterior  end  is  more  sharply  curved  and  slightly  an- 
gular, and  the  posterior  portion  from  the  extremity  of  the  hinge  to  the 
basal  border  very  slightly  flattened  or  truncate.  Beaks  anterior  to  the 
middle  of  the  valve,  directed  forward  and  approximate  at  their  apices  ; 
lunule  small  and  very  slightly  impressed  ;  ligament  proportionally  long, 
but  narrow,  the  shell  at  its  margins  slightly  incurved.  Body  of  the 
valve  ventrieose,  most  gibbous  on  the  utnbones  and  below,  while  an- 
teriorly and  posteriorly  the  shell  is  more  compressed  ;  umbonal  ridges 
not  defined. 

Surface  of  the  shell  smooth,  with  a  few  obsolete  or  faintly-  marked 
concentric  irregularities,  but  no  defined  varices  ;  fine  concentric  lines  of 
growth  are  seen  on  the  perfect  shells  under  an  ordinary  magnifier. 
Inner  margins  of  the  valves  smooth  ;  muscular  impressions  large  but 
faintly  marked,  submarginal  ;  pallial  line  deeply  sinuate,  the  apex  of 
the  sinus  being  directed  toward  the  beak  of  the  shell. 

The  shell  is  a  well-marked  species  of  Dosinia  so  far  as  the  characters 
have  been  ascertained,  but  the  hinge  structure  has  not  been  seen,  none 
of  the  casts  being  in  a  condition  to  show  the  teeth.  The  casts  are  quite 


24 

abundant  on  weathered  specimens  where  they  have  apparently  been 
subject  to  the  percolating  action  of  mineral  waters,  which  has  partially 
destroyed  them. 

Formation  and  locality. — In  Jurassic  rocks  at  the  top  of  the  highest 
hills,  two  miles  south  of  Belle  Fourche,  and  at  a  horizon  of  350  feet 
above  the  Triassic  red  beds,  east  of  Belle  Fourche ;  and  also  on  the  east 
side  of  Spear-fish  Greek,  near  junction  with  the  Ked  Water,  northeast 
of  Crow  Peak,  Black  Hills,  Dakota. 

FAM.  PSAMMOBinXE. 

GENUS  PSAMMOBIA,  Lam. 

.    PSAMMOBIA  !  PREMATURA,  n.  sp. 

Plate  5,  fig.  31. 

Shell  small,  transversely  elongated,  with  parallel  dorsal  and  basal  mar- 
gins, the  length  equaling  a  little  more  than  twice  the  height.  Valves 
very  depressed-convex  and  distinctly  gaping  at  each  end.  Beaks  small 
and  inconspicuous,  compressed,  situated  a  trifle  nearest  the  anterior  end  ; 
the  antero-cardiual  line  gradually  declining  with  a  very  slight  con- 
vexity to  the  narrowly-rounded  anterior  end,  basal  margin  straight  for 
more  than  half  the  length  of  the  shell,  rounding  upward  anteriorly  and 
posteriorly  j  postero-cardiual  line  a  very  little  lower  than  the  apex  of 
the  beak,  behind  which  it  is  straight  to  near  th-e  extremity  of  the  shell ; 
posterior  extremity  reaching  its  greatest  length  considerably  above  the 
middle  of  the  valve,  the  margin  being  directed  obliquely  forward  below 
to  the  end  of  the  basal  line.  Surface  of  the  valve  regularly  curved 
from  beak  to  base  and  from  the  posterior  umbonal  ridge  forward  to  the 
anterior  extremity  of  the  shell,  forming  nearly  a  level  line;  posterior 
to  the  umbonal  ridge  the  shell  is  depressed,  forming  a  broad  oblique 
sulcus  extending  from  behind  the  beaks  to  the  posterior  margin  of  the 
shell.  Muscular  markings  faint.  Pallia!  line  not  profoundly  sinuate, 
but  distinctly  emarginate  behind.  Hinge  and  teeth  unknown. 

The  species  is  only  recognized  by  single  valves,  but  the  form  is  so 
precisely  like  that  of  some  of  the  recent  Psammobias  that  it  seems 
unnatural  to  refer  it  to  any  other  genus.  The  parallel  dorsal  and  basal 
margins  and  the  form  of  the  posterior  slope  will  readily  distinguish  it 
from  any  other  shell  in  the  rocks  from  this  region. 

Formation  and  locality. — In  the  sandy  limestones  of  the  Jurassic  beds 
east  of  Belle  Fourche,  Black  Hills,  Dakota. 

GENUS  NE^ERA,   Gray. 
NE^ERA  LONGIROSTRA,  n.  sp. 

Plate  5,  fig.  35. 

Shell  very  small,  scarcely  exceeding  one  fourth  of  an  inch  in  length  ; 
transversely  elongate-ovate  or  clavate,  widest  anterior  to  the  middle, 


25 

and  narrowed  behind,  a  little  more  than  twice  as  long  as  high.  Valves 
very  convex,  becoming  inflated  near  the  middle  and  on  the  umbones. 
Beaks  proportionally  large,  erect,  strongly  projecting  above  the  hinge 
line,  and  situated  in  front  of  the  middle  of  the  length ;  anterior  end 
large  and  broadly  rounded,  somewhat  excavated  beneath  the  beaks; 
posterior  end  narrowed,  elongate,  and  very  slightly  recurved,  and  ob- 
liquely truncate  above  the  umbonal  angle;  basal  line  strongly  convex, 
more  distinctly  so  just  in  front  of  the  middle  opposite  the  beaks,  and 
broadly  constricted  behind ;  posterior  umbonal  ridge  very  faintly  an- 
gular, and  the  cardinal  slope  rather  abrupt. 

Surface  of  the  shell  marked  by  a  few  concentric  lines  of  growth,  and 
crossed  on  the  anterior  and  middle  parts  of  the  shell  by  a  few  propor- 
tionally strong,  elevated,  radiating  ridges,  to  the  number  of  eight  or 
nine,  with  wider  flattened  interspaces. 

The  species  is  small,  and  being  preserved  in  a  friable  sandstone,  the 
surface  characters  are  not  clearly  defined,  nor  can  any  of  the  hinge  or 
any  other  internal  features  be  seen. 

Formation  and  locality. — In  white  sandstones  of  Jurassic  age,  in  Red 
Water  Valley,  Black  Hills,  Dakota:  associated  with  Pseudomonotis 
curta,  Tancredia  Warrenana,  and  other  Jurassic  fossils. 

FAM.  GASTROCILEXIim 

GENUS  SAXICAVA,  Bettevue. 
SAXICAVA  JURASSICA,  n.  sp. 

Plate  5,  figs.  25-30. 

Shell  small,  elougate-subcylindrical,  with  subparallel  dorsal  and  basal 
margins ;  beaks  approximate,  distinct,  situated  near  the  anterior  end 
and  flattened  on  the  exterior  surface ;  umbonal  ridge  strongly  marked 
and  subangular,  placed  behind  the  middle  of  the  valve.  Anterior  end 
narrowed  and  very  slightly  excavated  below  the  beaks ;  posterior  ex- 
tremity wider  and  rounded  on  the  margin,  the  sides  being  laterally  com- 
pressed ;  basal  margin  very  gently  concave  in  the  middle  of  its  length. 
Body  of  the  valves  very  broadly  sulcated  between  the  anterior  end  and 
the  umboual  ridge,  and  somewhat  inflated  along  the  latter  feature  pos- 
terior to  the  middle  of  the  length.  Surface  of  the  shell  rather  distinctly 
marked  by  concentric  lines  parallel  to  the  margin,  which  are  elevated 
and  irregular,  but  not  lamellose ;  also  by  a  few  strong  undulations  of 
growth.  Just  below  the  hinge-line,  on  the  postero-cardinal  border,  the 
surface  strke  are  slightly  bent  and  the  surface  of  the  shell  very  slightly 
angular.  Internally,  as  seen  on  casts,  the  anterior  muscular  impression 
is  narrow,  and  situated  along  the  antero-basal  margin.  The  pallial  line 
appears  to  be  strongly  sinuate,  and  the  dorsal  margin  shows  evidence  of 
a  rather  strong  ligament.  The  casts  of  the  burrows,  as  seen  in  the  rock, 
are  almond  shaped,  or  very  elongate-ovate. 


26 

A  small  fragment  of  argillaceous  rock  in  the  collection  was  found  to 
contain  quite  a  number  of  the  burrows,  and,  on  being  broken,  a  few 
were  found  with  the  shells  in  position ;  but  in  an  effort  to  develop  them 
from  the  matrix,  the  shell  is  usually  removed  from  the  casts,  although, 
some  of  it  is  at  times  retained,  and  it  is  from  this  rather  imperfect  ma- 
terial that  the  description  has  been  drawn.  The  general  form  of  the 
shell  and  also  the  external  texture  would  seem  to  ally  them  with  the  an- 
gular group  of  the  genus  Lithodomus,  characterized  by  L.  gruneri  Phil- 
lipi,  but  the  sinus  of  the  pallial  line  would  seem  to  forbid  this  reference. 

Formation  and  locality. — In  rocks  of  Jurassic  age,  at  a  horizon  of  350 
feet  above  the  red  beds  of  the  Triassic,  at  Red  Water  Valley,  Black 
Hills,  Dakota. 


FOSSILS  OF  THE  CRETACEOUS. 


27 


MOLLUSCA. 

LAMELLIBEANCHIATA. 

FAM.  PTERIID^],  Meek. 

GENUS  PTERIA,  Scop. 
PTERIA  (PSEUDOPTERIA)  SUBLEVIS,  n.  sp. 

Plate  7,  fig.  6. 

Shell  small,  erect,  sub-rhomboid  or  sub-ovate  in  outline,  left  valve 
depressed-convex,  most  ventricose  on  the  umbo  and  toward  the  beak, 
near  which  it  becomes  subangular.  Hinge  line  shorter  than  the  length  of 
the  shell  below,  and  about  two-fifths  as  long  as  the  height ;  anterior  wing 
minute,  obtusely  pointed,  posterior  wing  moderate  in  size  and  convex, 
scarcely  separated  from  the  body  of  the  shell  by  a  slight  almost  imper- 
ceptibly depressed  line ;  anterior  side  of  the  shell  gradually  receding 
from  below  the  anterior  wing  to  the  basal  border,  which  is  rather 
sharply  rounded,  and  the  postero -basal  margin  a  little  more  sharply 
rounded  than  the  basal. 

The  surface  of  the  valve  in  all  the  specimens  seen  is  much  exfoliated, 
so  that  the  surface  features  are  not  positively  known,  but  it  has,  appar- 
ently, been  quite  smooth.  The  substance  of  the  shell  remaining  on  the 
specimens  is  highly  nacreous. 

Several  individuals  of  the  left  valve  have  been  noticed  in  the  collec- 
tion, but  none  of  the  right  have  been  recognized.  Those  seen  all  have 
the  same  character,  and  one  of  about  the  same  size,  being  a  little  less 
than  three-fourths  of  an  inch  in  length  by  about  half  an  inch  in  width. 
It  most  nearly  resembles  in  form  P.  (Pseudopteria)  fibrosa,  M.  &  H. 
(Paleont,  U.  S.  Geol.  Surv.  Territ,  p.  36,  pi.  17,  fig.  17),  but  differs  en- 
tirely in  the  surface  features,  being  entirely  destitute  of  the  faint  plica- 
tion of  that  species. 

Formation  and  locality. — In  limestone  of  Cretaceous  age,  ]N~o.  4,  Old 
Woman's  Fork,  Black  Hills,  Dakota. 

Among  the  collections  from  the  Fort  Pierre  group  there  are  large 
numbers  of  Inocerami,  representing  several  of  the  species  and  varieties 
recognized  by  Mr.  F.  B.  Meek,  in  his  excellent  work  on  the  Upper  Mis- 
souri Cretaceous  formations,  just  issued  by  the  Department  of  the  In- 
terior. But  notwithstanding  the  careful  manner  in  which  these  forms 
have  been  described  and  figured  by  that  author,  we  find  great  difficulty 

29 


30 

in  arriving  at  any  very  satisfactory  conclusions  as  to  the  limits  of  species 
when  so  large  a  collection  is  examined.  The  species,  as  figured  in  the 
above-mentioned  work,  appear  distinct  enough,  and  the  lines  of  demarka* 
tion  well  drawn,  when  a  few  individuals  only  are  before  one,  but  among 
the  collections  in  hand  we  find  the  boundaries  crossed  in  every  direc- 
tion, so  that  we  are  at  a  loss  in  many  cases  for  characters  by  which  to 
separate  the  different  forms  there  indicated,  while  there  are  still  others 
among  them  so  entirely  different  from  any  of  those  described  and  fig- 
ured that  we  are  very  reluctantly  compelled  to  consider  them  as  entirely 
distinct. 

Among  the  forms  representing  those  given  under  the  names  J. 
Vaunxemi,  I.  proximus,  and  I.  proximus,  var.  subcircularls,  and  also 
as  1.  convexus  and  J.  Sagensis,  var.  Nebrascensis  and  I.  Balchii,  we  find 
such  gradually  connecting  links  as  to  make  it  extremely  difficult  if  not 
impossible  to  draw  lines  of  distinction  between  them.  Again,  those  re- 
sembling the  forms  given  under  the  names  I.  Cripsiij  var.  Barabini  and 
J.  tennilineatus,  are  similarly  united. 

The  forms  which  we  had  referred  to  I.  Sagensis  and  1.  Nebrascensis 
of  Owen,  vary  so  greatly  in  the  posterior  prolongation  of  the  shell  and 
also  in  the  direction  of  the  basal  margin  as  to  defy  all  attempts  to  class- 
ify them  by  their  form,  and  in  the  relative  degree  of  convexity  and  the 
comparative  distance  of  the  surface  undulations  they  are  eqally  variable 
and  unsatisfactory.  We  find  also  that  the  relative  projection  of  the 
beaks  and  the  width  of  the  cartilage  arear  as  well  as  the  distance  of  the 
beaks  from  the  anterior  end,  is  subject  to  great  variation.  Although 
in  the  collection  before  us  there  are  but  few  individuals  which  retain 
the  right  and  left  valves  in  contact,  still  of  many  of  them  we  have  both 
valves  of  similar  size  and  form  from  the  same  locality,  and  we  find  that 
the  difference  in  convexity  between  the  two  valves  is  not,  in  any  case, 
very  great,  and  often  scarcely  perceptible.  The  beak  of  the  left  valve 
is  usually  larger  and  projects  more  beyond  the  line  of  the  hinge  than 
that  of  the  right,  and  the  cartilage  area  is  a  little  wider.  Perhaps  if  the 
real  surface  features  of  the  shells  were  preserved  on  the  specimens 
more  reliable  characters  for  specific  distinction  might  be  presented, 
but  the  fibrous  coating  is  almost  always  absent,  being  generally  left  in 
the  matrix  and  not  collected,  or  perhaps  in  many  cases  removed  by 
some  action  of  decay  before  the  shells  are  finally  imbedded  in  the  rocky 
sediment,  so  that  in  collections  it  is  seldom  that  any  part  of  this  layer 
is  retained  on  the  specimens,  except  a  little  around  the  beaks  or  along 
the  hinge  margins.  Owing  to  these  difficulties,  the  same  that  Mr.  Meek 
has  found  to  exist  among  his  specimens,  and  also  to  the  impossibility  of 
giving  a  sufficient  number  of  figures  to  show  fully  and  clearly  the  vari- 
ations which  we  have  found  among  the  examples  in  hand,  we  shall  be 
obliged  to  follow  very  nearly  the  same  specific  limits  which  that  author 
has  found  desirable,  though  we  must  confess  that  in  some  cases  we 
should  prefer  rather  to  consider  some  of  the  forms  found  associated  to- 


31 

gether  in  the  same  localities  and  presenting  only  slight  differences,  as 
one  and  the  same  species,  than  to  identify  these  far  western  forms  with 
species  described  from  Europe,  as  has  been  done  by  so  many  authors. 
We  do  not  dispute  their  great  resemblances,  but  believe  them  to  be 
rather  representative  species  than  equivalent  forms. 

INOCERAMUS  PERPLEXUS,  n.  sp. 

Plate  8,  fig.  3,  and  plate  10,  figs.  4  and  5. 

Shell  rather  below  the  medium  size,  erect,  truncate,  subovate  in  out- 
line, shortest  at  the  hinge-line,  and  gradually  expanding  to  below  the 
middle  of  the  height ;  valves  convex ;  beaks  terminal,  slightly  inclined 
forward,  pointed,  and  incurved ;  hinge-line  short  and  straight,  not 
exceeding  two-thirds  of  the  length  below  in  any  of  the  examples  seen ; 
anterior  border  straight  or  very  slightly  concave  for  more  than  half  the 
height  of  the  shell,  where  it  unites  with  the  deeply  rounded  basal 
border;  posterior  margin  of  the  shell  gradually  widening  from  the 
extremity  of  the  hinge-line  to  the  point  of  greatest  width,  in  an  antero- 
posterior  direction,  which  is  rather  below  the  middle  of  the  height, 
where  it  unites  in  a  regular  curve  with  the  basal  margin.  Valves  most 
strongly  convex  along  the  umbonal  ridge,  which  is  situated  nearest  to 
the  anterior  side  of  the  shell  and  slopes  gradually  to  the  postero- 
cardinal  portion,  where  it  becomes  almost  flattened ;  while  the  anterior 
border  is  vertical,  or  sometimes  slightly  concave,  for  more  than  half  the 
depth  of  the  valve. 

{Surface  of  the  shell  marked  by  strong,  irregular,  concentric  folds  or 
undulations,  parallel  to  the  margin  and  passing  off  on  the  vertical 
anterior  border.  Substance  of  the  inner  layers  highly  nacreous.  Fibrous 
coating,  when  preserved,  apparently  thin. 

This  species  is  somewhat  remarkable  for  its  erect  form  and  strong 
concentric  undulations.  In  form  it  resembles  the  specimens  of  I.  fragilis 
Hall  and  Meek,  given  by  the  latter  author,  (Pal.  U.  S.  Geol.  Surv. 
Territ,,  p.  42,  figs.  1  2),  but  in  the  surface  characters  it  is  entirely  dis- 
tinct from  that  species,  and,  when  compared  with  examples  of  that 
species  having  the  characters  of  the  original  specimen,  is  very  readily 
distinguished.  It  also  somewhat  resembles  I.  JSllioti  Gabb  from  the 
Cretaceous  sandstones  of  San  Francisco  Harbor,  Gal. 

Formation  and  locality. — In  concretionary  limestone  at  the  top  of 
shales  of  Cretaceous  Xo.  2,  on  the  Belle  Fourche,  about  ten  miles  west 
of  Crow  Peak,  Black  Hills,  Dakota. 

ENDOCOSTEA,  new  gen. 

Shell  resembling  Inoceramus,  being  bivalve,  with  both  sides  convex, 
but  more  or  less  unequal,  and  composed  of  two  layers,  an  outer  verti- 
cally fibrous  coating  and  an  inner  nacerous  or  pearly  lining ;  hinge-line 
straight,  edentalous,  with  a  narrow  linear  external  cartilage  area  on 


32 

each  valve.  Yalves  provided  with  an  oblique  internal  rib,  passing  from 
behind  the  beaks,  along  the  postero-cardinal  slope,  toward  the  postero- 
basal  margin,  marking  the  position  of  the  posterior  muscular  imprint. 
Other  muscular  marking  unknown.  Type,  =  E.  Typica,  Whitf. 

We  have  not  been  able  to  detect  the  anterior  muscular  scar  or  pallial 
line,  except  the  latter  as  an  irregular  transverse  line  of  small  tubercles 
across  the  beak  of  internal  casts  in  several  cases,  and  a  slight,  curving 
ridge,  faintly  marked  on  a  smaller  number  of  examples,  passing  from 
the  apex  along  the  anterior  side  for  a  short  distance.  The  genus  differs 
from  Inoceramus,  so  far  as  yet  known,  only  in  the  existence  of  the 
internal  rib.  The  species  now  known  are  E.  alveatus  =  Inocemmus  alve- 
atuSj  Morton ;  E.  impressus  =  I.  impressus,  D'Orb. ;  E.  sulcatus  =  I.  cripsii 
var.  Sulcatus,  Eoemer ;  and  E.  typica,  Whitf.,  herein  described. 

ENDOCOSTEA  TYPICA,  n.  sp. 

Plate  9,  figs.  1-7. 

Shell  of  medium  size,  transversely  subovate,  oblique,  and  slightly  ine- 
quivalve,  the  right  side  being  the  largest  in  the  only  example  where 
they  are  preserved  in  contact.  Valves  strongly  ventricose  at  the  ante, 
rior  end  and  on  the  anterior  part  of  the  umbonal  region,  becoming  more 
compressed  and  attenuate  behind  and  along  the  posterior  cardinal  por- 
tion, sometimes  strongly  depressed  and  concave  between  the  cardinal 
line  and  dorsal  slope.  Hinge-line  straight,  often  two-thirds  as  long  as 
the  shell  below,  and  slightly  rounded  at  the  extremity.  Beaks  small, 
incurved,  projecting  but  little  above  the  cardinal  line,  and  situated  near 
the  anterior  end,  but  not  quite  terminal.  Anterior  end  short,  sharply 
rounded  at  the  antero-cardinal  angle,  and  extending  a  little  forward 
below  for  about  half  the  height  of  the  valve,  when  it  rounds  backward 
to  the  basal  line,  the  upper  part  forming,  with  the  cardinal  line,  an  angle 
of  about  95°  to  100°.  Posterior  end  nearly  equal  to,  or  narrower  than, 
the  anterior,  and  more  sharply  rounded,  most  strongly  from  below. 
Basal  line  forming  nearly  half  of  an  ellipse,  or  semiovate,  the  widest 
part  varying  from  in  front  of  to  behind  the  middle  of  the  length,  in 
different  individuals.  Surface  of  the  valves  usually  marked  by  very 
distinct  concentric  undulations,  though  sometimes  they  are  only  moder- 
ately developed.  Oblique  internal  rib  strongly  marked,  narrow  and 
pointed  near  the  beak,  and  gradually  widening  and  deepening  posteri- 
orly, the  concentric  furrows  distinctly  crossing  and  leaving,  on  the 
deeply  concave  channel  of  the  casts,  corresponding  depressions.  Inner 
layers  of  the  shell  highly  nacreous ;  outer  prismatic  layer  very  thin. 

This  species  resembles  Inoceramus  Barabini,  as  it  is  recognized  in  the 
same  region,  in  the  general  form  and  in  the  subcuneate  anterior  end  of 
the  shell;  but  the  concentric  furrows  are  generally  more  distinctly 
marked  and  regular.  It  is  readily  distinguished  by  the  oblique  sulcus 
and  by  the  opposite  valve  being  the  largest,  if  the  example  above  refer- 
red to,  and  figured  on  the  plate,  is  rightly  interpreted. 


33 

We  have  great  doubts  of  tbe  identity  of  the  western  forms  with  I. 
BaraUni  Morton,  from  Alabama,  and  are  inclined  to  believe  they  would 
be  more  naturally  classed  under  a  distinct  name,  as  formerly  done  by 
Messrs.  Meek  &  Hayden. 

Formation  awl  locality. — In  limestone  of  the  Fort  Pierre  group,  at  Old 
Woman's  Fork  of  the  Cheyenne  River,  Black  Hills,  Dakota,  where  they 
occur  very  abundantly,  densely  packed  together  in  the  rock,  and  pos- 
sessing the  specific  characters  and  the  oblique  sulcus  in  a  remarkably 
constant  degree. 

MCULASID^E. 
Genus  NUCULANA. 

XUCULANA   SUBEQUILATERA,   11.  Sp. 
*  Plate  11,  figs.  3  and  4. 

Shell  of  small  size,  transversly  elongate-subovate,  with  large,  promi- 
nent, suberect  beaks  which  are  placed  a  little  in  advance  of  the  middle 
of  the  length,  and  are  slightly  incurved,  but  comparatively  distant. 
Valves  convex,  as  seen  on  the  casts,  ventricose  in  the  middle  and  below 
the  beaks,  and  compressed  toward  the  extremities ;  more  particularly 
so  posteriorly ;  hinge-line  abruptly  bent  between  the  beaks,  the  opposite 
sides  forming  an  angle  of  about  140°,  the  posterior  side  slightly  recur- 
ring in  the  outer  part ;  anterior  end  of  the  shell  sharply  rounded ;  pos- 
terior extremity  acutely  rounded  near  the  extremity  of  the  cardinal  line, 
and  rapidly  sloping  forward  below  to  the  basal  margin,  which  is  broadly 
curved  and  almost  straightened  in  the  middle. 

Surface  of  the  shell  unknown ;  hinge-plate  marked  by  a  large  num- 
ber of  comparatively  long,  slender  teeth,  minute  in  the  middle,  and 
gradually  increasing  in  size  and  length  outwardly ;  about  twenty  may, 
with  difficulty,  be  counted  on  the  posterior  side  of  the  beaks,  and  about 
eighteen  on  the  shorter  side.  Cartilage  pit  small ;  muscular  imprints 
faintly  marked.  Xo  sinus  can  be  detected  in  the  pallial  line. 

The  species  seems  to  be  nearly  related  to  Nucula  (Nuculanaf)  equilat- 
eralis,  M.  &  H.,  but  the  beaks  are  not  central  as  in  that  species,  but 
are  situated  at  about  two-fifths  of  the  length  from  the  anterior  end,  and 
the  teeth  are  decidedly  not  obtuse,  but  on  the  contrary  are  very  slender, 
as  seen  on  the  casts. 

Formation  and  locality. — In  Cretaceous  rocks  on  the  Cheyenne  Itiver, 
near  French  creek  ;  supposed  to  be  very  near  the  top  of  the  Fort  Pierre' 
group. 

3  B  H 


34 

FAM.  CRASSATELLIDJE. 
GENUS  CRASSATELLA,  Lam. 
CRASSATELLA  SUBQUADRATA,  n.  sp. 

Plate  11,  fig.  12. 

Shell  small,  subquadrangular  in  outline,  with  thin,  compressed  valves 
and  not  prominent  beaks,  which  are  situated  within  the  anterior  third 
of  the  length ;  length  of  the  shell  exceeding  the  height ;  basal  margin 
broadly  rounded ;  anterior  end  short  and  narrowly  rounded  ;  posterior 
end  broad  and  rounded  truncate ;  posterior  hinge-line  straight  and  sub- 
parallel  to  the  basal  margin.  Surface  of  the  shell  unknown.  Muscular 
impressions  small;  the  posterior  one  situated  close  beneath  the  extremity 
of  the  hinge-margin,  and  the  anterior  scar  subinarginal.  Pallia!  line 
not  distinctly  marked;  margin  of  the  valves  crenulate. 

The  only  specimen  of  this  genus  recognized  among  the  collections 
from  the  Black  Hills  is  a  small  internal  cast,  answering  to  the  above 
description,  and  apparently  a  true  Orassatella.  Although  the  extremity 
of  the  hinge-plate  has  not  been  seen,  the  cast  has  all  the  features  usually 
possessed  by  casts  of  the  typical  forms  of  the  genus. 

Formation  and  locality.— In  Cretacous  beds  on  the  Cheyenne  River ; 
probably  from  the  Fort  Pierre'  group. 

CTPEINID^E. 

GENUS  SPILERIOLA. 
SPH^ERIOLA  TRANSVERSA,  n.  sp. 

Plate  10,  figs.  14-16. 

Shell  of  rather  large  size,  subsphaeroidal,  a  little  transverse,  or  longer 
than  high,  exclusive  of  the  projection  of  the  beaks,  the  outline  of  the 
margin  of  the  valve  being  slightly  oblate  or  transversely  broad-oval,  and 
nearly  symmetrical.  Valves  highly  inflated  on  the  central  area  and 
umbones,  with  strong,  highly-elevated,  strongly-incurved,  subcentral 
beaks,  which  are  slightly  curved  forward  and  subangular  on  the  um- 
bonal  ridges. 

Surface  of  the  shell  marked  by  sublamellose,  concentric  lines  of  growth , 
which  form  strong  distant  undulations  in  some  cases  toward  the  ex- 
tremities of  the  shell. 

Internally  the  muscular  impressions  are  large  and  subcircular,  and 
the  pallial  line  simple  and  entire.  The  cardinal  teeth,  as  obtained  by  a 
gutta-percha  mold  from  a  natural  cast,  consist  of  two  tuberculiform 
teeth  beneath  the  beak,  and  the  laterals  are  represented  by  a  strong 
oblique  fold  or  ridge  passing  from  near  the  beak  to  within  a  short  dis- 


35 

tance  of  the  posterior  border  of  the  hinge-plate,  where  it  is  marked  or 
divided  by  au  impressed  pit,  which  may  be  accidental. 

Compared  with  S.  obliquata  Meek,  this  shell  is  more  equilateral,  the 
beaks  more  nearly  central,  and  the  shell  less  oblique.  It  differs  from 
S.  Moreanenris  of  the  same  author  in  having  much  larger  beaks,  more 
strongly  enrolled,  and  the  shell  is  also  more  transverse. 

Formation  and  locality. — In  ferruginous  sandstone  of  Cretaceous  Xo.5. 
On  Che  Cheyenne  River,  near  Old  Woman's  Fork,  Dakota. 

ZELLINIDJ^. 

GENUS  LIOPISTHA,  Meek 

SUBMENUS  CYMELLA,  Meek-. 

LEIOPISTHA  (CYMELLA)  MEEKI,  n.  sp. 

Plate  11,  figs.  27  and  23. 

Shell  of  moderately  large  size,  transversely  oval  in  outline,  about  once 
and  a  half  as  long  as  high.  Valves  very  convex,  with  large,  tumid,  in- 
curved beaks,  which  are  located  a  little  more  than  one-third  of  the  entire 
length  from  the  anterior  end  of  the  shell,  and  are  considerably  elevated 
above  the  cardinal  line ;  anterior  and  posterior  ends  of  the  valve  broadly 
and  nearly  equally  rounded,  and  the  basal  line  between  the  longest 
points  of  the  shell  forming  a  very  regular  and  nearly  symmetrical  semi- 
oval  curve ;  cardinal  line  sloping  gradually  on  both  sides  of  the  beak, 
the  anterior  side  marked  by  a  narrow,  lanceolate,  lunule-like  depression, 
and  the  posterior  side  by  a  larger,  broader  area,  bordered  by  an  elevated 
ridge.  Concentric  undulations  of  the  surface  strong  and  distinct,  con- 
tinuing their  sharpness  to  the  margins  of  the  cardinal  depressions,  and 
gradually  increasing  in  strength  with  the  increased  size  of  the  shell  to 
below  the  middle,  beyond  which  point  they  become  flattened  and  fainter ; 
about  twenty-seven  may  be  counted  on  the  entire  surface.  The  concentric 
undulations  are  crossed  by  comparatively  strong  radiating  cost®,  which 
do  not  mark  the  depressions  between  the  undulations,  but  exist  only  on 
their  flattened  surfaces.  The  radii  are  strongest  on  the  central  parts  of 
the  shell  and  become  gradually  finer  and  closer  toward  the  lateral  ex- 
tremities, and  are  visible  on  the  anterior  end  to  the  margin  of  the  car- 
dinal depression,  but  on  the  posterior  end  are  not  seen  to  exist  quite  so 
far.  The  crests  of  the  radii  appear  to  have  been  marked  by  a  row  of 
minute  puncta,  seen  only  under  a  magnifier,  three  and  four  existing  to 
each  undulation.  The  surface  of  the  shell  is  also  marked  by  fine,  some- 
what wrinkled,  concentric  lines  of  growth,  especially  on  the  larger  parts 
of  the  valve,  but  apparently  confined  to  the  outer  coating  of  the  shell, 
and  presenting  the  appearance  of  a  thick  epidermis. 

We  were  at  first  inclined  to  consider  this  as  P.  umlulata  M.  &  H.,  but 
on  strict  comparison  with  Mr.  Meek's  description  in  the  Pal.  of  the  U.  S. 


36 

Geol.  Surv.  Territ.,  which  we  have  just  received,  have  concluded  it  to 
be  a  different  species.  It  differs,  first,  in  the  greater  size  and  more 
robust  habits,  also  in  the  comparatively  stronger  undulations,  and  in 
having  the  radiating  costse  continuing  to  the  anterior  end  if  not  to  the 
posterior  also.  The  outline  of  the  shell  also  differs  somewhat. 

Formation  and  locality. — In  Cretaceous  strata  at  Dead  Man's  Rapids, 
Upper  Missouri.  Probably  of  No.  5. 

FAM.  AXATINID  J]. 

GENUS  THRACIA,  Leach. 
THRACIA  SUBGRACILIS,  n.  sp. 

Plate  11,  figs.  29  and  30. 

Shell  small,  transversely  ovate  and  slightly  iuequivalve,  valves  con- 
vex, veutricose  in  the  middle,  but  becoming  quite  compressed  and  al- 
most constricted  behind ;  anterior  part  large,  forming  nearly  or  quite 
four-fifths  of  the  entire  bulk  of  the  shell,  the  extremity  rounded ;  basal 
line  full  in  front  of  the  beaks  and  constricted  or  sinuate  behind ;  posterior 
end  narrow  and  subtruncate ;  anterior  cardinal  line  long,  nearly  on  a 
line  with  the  beaks  and  very  slightly  convex ;  posterior  to  the  beaks 
the  cardinal  line  is  constricted  and  narrowed  $  beaks  small  and  com- 
pressed, appearing  as  if  directed  backward. 

The  surface  of  the  only  specimen  is  imperfect,  the  shell  being  in  great 
part  removed,  but  where  preserved  is  marked  by  concentric  lines  of  con- 
siderable strength,  approaching  in  character  to  undulations  rather  than 
striae.  The  beaks  are  small  and  marked  along  their  apices,  and  for  a 
short  distance  below,  by  a  slight  notch  or  slit,  from  the  removal  of  a 
narrow  ridge  which  has  marked  the  interior  of  the  shell,  as  in  Anatina, 
and  supporting  the  cartilage-pit.  The  shell,  in  its  external  form,  has 
all  the  features  of  Thracia,  being  slightly  inequivalve  and  also  slightly 
twisted  when  viewed  in  profile,  and  also  in  the  character  of  the  surface 
markings.  The  muscular  impressions  or  pallial  line  cannot  be  distin- 
guished through  the  remaining  shell,  and  we  are  therefore  in  doubt  con- 
cerning these  features.  It  bears  considerable  resemblance  to  Thraqia 
gracilis  M.  &  H.  (Pal.  U.  S.  Geol.  Surv.  Territ.,  p.  224,  PI.  30,  fig.  6), 
but  is  proportionally  shorter  and  somewhat  more  contracted  in  height 
posteriorly. 

Formation  and  locality. — In  Cretaceous  rocks,  probably  near  the  top 
of  No.  4;  near  French  Creek,  on  the  Cheyenne  River,  Dakota. 


37 

GASTEROPODA. 

FUSUS  CHEYENNENSIS,  n.  8p. 

Plate  12,  fig.  9. 

Shell  small,  spire  slender  and  elevated,  the  number  of  volutions  un- 
known, but  probably  six  or  more,  strongly  rounded,  the  last  one  some- 
what ventricose  above  the  middle  but  attenuate  below  ;  aperture  semi- 
ovate,  being  rather  straightened  on  the  inner  side  and  slightly  produced 
below.  Volutions  crossed  by  numerous  vertical  folds  or  plica?,  which 
are  very  slightly  bent  backward  in  their  course  across  the  volution. 
Surface  of  the  shell  unknown. 

The  specimen  from  which  the  description  is  drawn  is  an  internal  cast, 
and  therefore  the  external  characters  cannot  be  given  in  detail.  The 
species  is,  however,  so  entirely  distinct  from  any  of  the  forms  known 
from  this  region,  that  there  is  no  fear  of  its  being  confounded  with  any 
of  them. 

Formation  and  locality. — In  the  gray  shales  near  the  upper  part  of  the 
Fort  Pierre  group.  On  the  Cheyenne  River,  near  Rapid  Creek,  Black 
Hills,  Dakota. 

APORRHAI^  MEEKI,  n.  sp. 

Plate  12,  fig.  5. 

Shell  of  moderate  size,  with  a  low,  very  obtusely  pointed  spire,  which 
is  composed  of  only  three  ventricose  or  rounded  volutions,  exclusive  of 
the  apertural  expansion,  and  which  rapidly  increase  in  size ;  apical  angle 
nearly  eighty  degrees.  Volutions  marked  by  numerous  sharply  elevated 
revolving  lines,  with  concave  interspaces  both  above  and  below  the 
middle.  Outer  lip  expanded,  and  extended  into  two  diverging  carinated 
digitations  of  an  undetermined  length,  which  are  deeply  grooved  on  the 
inner  face,  the  upper  one  being  directed  slightly  backward  toward  the 
spire,  and  the  other  one  slightly  downward  and  more  strongly  forward 
in  the  direction  of  the  coil  of  the  shell ;  anterior  beak,  judging  from  the 
part  remaining,  moderately  long  and  stout ;  posterior  canal  extending 
along  the  spine  to  the  summit,  where  it  appears  to  have  become  free 
and  deflected ;  callous  slight(?),  coating  the  upper  volutions  over  a  part 
of  their  extent. 

This  species  differs  from  any  previously  described  form  of  this  group, 
in  the  short  obtuse  spire,  combined  with  the  two  digitations  of  the  outer 
lip,  and  the  posterior  canal  which  extends  to  the  summit  of  the  spire. 

Formation  and  locality. — In  limestone  of  the  Fort  Pierre  group,  at  the 
top  of  the  gray  shales  of  this  formation.  On  the  Cheyenne  River,  near 
Rapid  Creek,  Black  Hills,  Dakota. 


38 
APORRHAIS  (G-ONIOCHEILA)  CASTORENSIS,  n.  sp. 

Plate  12,  fig.  1. 

Shell  small,  with  a  moderately  elevated  spire,  composed  of  about  four 
flattened  or  very  slightly  veutricose  volutions,  which  are  crossed  by  fine 
flexuous,  vertical  folds,  strongly  directed  forward  in  their  course  across 
the  whorl,  and  also  marked  by  fine  thread-like  revolving  lines ;  suture 
distinct;  apical  angle  about  40°,  but  slightly  variable  on  different 
individuals.  Body  volution  proportionally  large  and  very  strongly 
angular,  or  even  carinate,  along  the  middle,  flattened  or  sMghtly  concave 
on  the  upper  surface  and  rapidly  contracted  below  to  the  short,  pointed 
rostral  beak.  A  second  rather  indistinct  carination  marks  the  surface 
a  little  below  the  first,  but  seldom  or  never  extends  to  the  margin  of  the 
lip.  Outer  lip  expanded,  strongly  carinate  on  the  back  and  projecting 
in  the  middle,  to  form  a  short,  obtuse,  slightly  recurved  digitation,  and 
posteriorly  extending  along  the  spire  to  the  base  of  the  second  volution 
above. 

This  species  somewhat  resembles  A.  biangulata,  M.  &  H.  (Pal.  U.  S. 
Geol.  Surv.  Territ.,  p.  322,  pi.  19,  fig.  6),  but  differs  in  the  subdued 
character  of  the  lower  carination  and  in  the  strongly  uuiaugular  form  of 
the  body  volution.  Among  a  number  of  specimens  none  show  the  pos- 
terior canal  extending  above  the  point  described,  nor  any  evidence  of  a 
second  digitation  to  the  lip.  The  surface  markings  are  quite  superficial, 
but  few  specimens  showing  them,  appearing  quite  smooth  from  slight 
exfoliation. 

We  are  extremely  averse  to  describing  new  species  of  this  group  of 
shells,  as,  from  their  extreme  liability  to  variation  with  different  degrees 
of  development,  they  are  easily  mistaken  ;  and  we  have  feared  that  this 
might  prove,  on  the  examination  of  a  larger  and  better  collection  of 
specimens,  to  be  only  a  form  of  A.  Uangulata,  M.  &  H.,  above  referred 
to;  but  the  single  strong  carination,  and  the  fact  that  it  comes  from  a 
lower  geological  horizon  and  distant  locality,  have  induced  us  to  separ- 
ate it  under  a  new  name. 

Formation  and  locality. — In  a  ferruginous  sandy  limestone,  on  the 
East  Fork  of  Beaver  Creek,  Black  Hills.  Associated  with  fossils  of  the 
Fort  Beuton  group. 

GEXUS  AKKRA,   0.  F.  Muller. 

AKERA  GLANS-ORYZA,  n.  sp. 

» 

Plate  12,  fig.  25. 

Shell  minute,  not  exceeding  one-fifth  of  an  inch  in  length,  and  the 
diameter  being  about  twice  and  a  half  less  than  the  length ;  cylindrical 
in  form,  with  a  very  low,  truncated  spire,  which  consists  of  about  three 
or  three  and  a  half  volutions,  the  outer  margins  of  which  are  bordered 


39 

by  ail  elevated  kiiife-edge  carina,  giving  a  deeply  channeled  convolute 
character  to  the  spire,  the  center  scarcely  rising  above  the  level  of  the 
outer  carination.  Body  of  the  outer  volution  very  slightly  rounded  near 
the  margin  of  the  flattened  spire,  and  distinctly  so  to  the  base  below. 
Aperture  as  long  as  the  shell,  narrow  above  and  gradually  widening  and 
rounded  at  the  base.  Columella  curved  and  apparently  reflected  upon 
the  preceding  volution.  Axis  imperforate. 

Surface  of  the  shell  marked  by  very  fine,  revolving,  impressed  lines, 
strongest  near  the  top  of  the  volution  and  on  the  lower  third ;  also  by 
finer  transverse  striae  of  growth,  parallel  to  the  margin  of  the  aperture, 
and  indicating  by  their  direction  that  the  central  portion  of  the  outer 
lip  is  a  little  in  advance  of  the  top  and  base. 

Formation  and  locality. — In  limestone,  near  the  top  of  the  Fort  Pierre 
group.  On  the  Cheyenne  River,  near  French  Creek,  Black  Hills,  Dakota. 

CEPHALOPODA. 

GEXCS  HELICOCERAS,  VOrb. 

HELICOCERAS  STEVENSONI,  n.  sp. 

Plate  14,  figs.  4-7. 

Shell  large  and  robust,  with  an  elevated,  moderately  tapering  spire, 
which  is  composed  of  strong,  cylindrical,  disconnected,  dextrally  coiled 
volutions,  sharply  enrolled  *and  leaving  an  umbilical  opening  equal  to, 
or  a  little  greater  than,  one-half  the  diameter  of  the  volution  encircling 
it.  The  volutions  are  at  first  widely  disconnected  and  rapidly  descend- 
ing, but  become  more  closely  coiled  below,  and  in  the  lower  part  of  the 
example  figured  are  but  slightly  disconnected. 

Surface  of  the  shell  marked  by  strong,  rounded,  annulatiug  costa, 
passing  entirely  around  the  shell,  and  separated  by  wider  concave  inter- 
spaces. On  the  upper  surface  of  the  volution  the  costa  are  strongly 
directed  backward,  but  are  recurved,  and  on  the  outer  face  are  directed 
gently  forward  below  and  within  the  umbilicus.  The  costa  are  farther 
ornamented  by  two  irregular  rows  of  strong,  obliquely-rounded,  tuber  - 
culose  nodes,  the  upper  range  being  situated  along  the  middle  of  the 
volution,  and  the  other  half-way  between  it  and  the  center  of  the  basal 
surface.  The  nodes  of  the  two  ranges,  although  usually  placed  on  the 
same  costa,  are  not  constantly  so,  but  frequently  alternate,  and  in  very 
many  cases  two  of  the  costa  unite  at  the  lower  node,  continuing  only 
as  one  on  the  lower  side  of  the  volution. 

Septa  rather  distantly  arranged,  leaving  considerable  space  between 
them,  the  convolutions  of  a  single  septum  occupying  a  space  on  the 
periphery  of  the  shell,  equal  to  from  two-thirds  to  three-fourths  of  the 
diameter  of  the  volution,  at  the  point  examined.  Siphonal  lobe  longer 
than  wide,  and  deeply  divided  at  the  extremity  into  two  principal 
branches,  each  of  which  are  again  deeply  divided,  and  the  divisions 


40 

furnished  with  numerous  serrated  digitations.  First  lateral  lobe  very 
large  and  unequally  divided  into  two  principal  branches,  the  outer  one 
of  which  is  the  largest,  and  each  is  again  divided  and  furnished  with 
numerous  compound  digitations.  The  second  lateral  lobe  is  much 
smaller  than  the  first,  and  similarly  divided,  but  the  divisions  are  smaller 
and  less  complicated.  (The  inner  half  of  this  lobe  has  not  been  distinctly 
traced.)  First  lateral  sinus  rather  large  and  deeply  cleft  in  the  middle 
by  an  auxiliary  lobe,  the  lower  end  of  which  is  divided  into  several  digi- 
tations. Second  lateral  sinus  shorter  and  comparatively  more  spreading 
than  the  first  also,  and  deeply  divided  in  the  middle  by  a  simple  auxili- 
ary lobe  having  four  spurs  on  each  side.  Other  lobes  and  sinuses  not 
observed.  Siphuncle  rather  small,  marginal,  and  passing  along  the  mid- 
dle of  the  volution. 

This  species  would  appear,  without  critical  examination,  to  be  some- 
what closely  related  to  Heteroceras  f  angulatum,  M.  &  H.  (Pal.  U.  S.  Geol- 
Surv.  Ten-it.,  p.  484,  pi.  21,  fig.  3),  more  especially  as  their  species  is 
stated  to  be  "(dextral?)";  and  their  figures,  being  placed  base  upward, 
which  may  be  seen  by  the  position  of  the  nodes,  are  liable  to  mislead, 
but  if  critically  examined  will  be  found,  from  the  direction  of  the  costa, 
to  belong  to  a  sinistral  shell,  as  they  incline  in  an  opposite  direction  to 
those  of  a  dextral  shell.  Mr.  Meek  states  loc.  cite  that  the  fragment 
figured  is  supposed  to  be  from  the  deflected  part  of  the  shell,  and  for 
this  reason  is  placed  provisionally,  with  doubt,  under  the  genus  Hetero- 
ceras. It  is,  perhaps,  impossible  for  one  to  feel  positive  that  a  shell  of 
this  group  has  not  been,  or  would  not  be,  deflected  at  some  period  of 
growth,  unless  a  perfect  adult  individual  is  obtained.  Our  shell  figured 
shows  no  evidence  whatever  of  any  tendency  to  become  deflected  ;  still 
it  is  known  to  be  imperfect,  as  it  is  septate  to  within  an  inch  of  the 
outer  extremity,  and  we  cannot  therefore  feel  positive  of  its  true  generic 
relations.  The  upper  part  of  the  spire  has,  however,  been  very  loosely 
coiled,  or  widely  disconnected,  becoming  more  compact  with  increased 
growth  5  in  this  respect  being  the  reverse  of  shells  belonging  to  the  genus 
Heteroceras.  Owing  to  this  feature,  and  the  absence  of  any  evidence  of 
the  generically-required  deflection  in  the  adult  stages,  we  have  con- 
sidered it  most  natural  to  refer  it  to  Helicoceras. 

Formation  and  locality. — In  limestone  of  the  Fort  Pierre  group,  on 
the  west  side  of  Beaver  Creek,  southwest  Black  Hills. 

GENUS  HETEROCERAS,  D'Orb. 
HETEROCERAS  NEWTONI,  n.  sp. 

Plate  15,  figs.  1-4. 

Shell  dextral,  of  moderate  size,  composed  of  from  two  and  a  half  to 
three,  loosely  coiled,  disconnected,  and  rather  rapidly  increasing 
volutions  forming  the  rather  low  but  somewhat  rapidly  spreading 


41 

> 

spire,  below  which  point  the  shell  is  deflected  to  an  unknown  extent. 
Transverse  section  of  the  shell  circular,  or  nearly  so.  Umbilicus  very 
wide  in  the  upper  part  of  the  spire,  but  scarcely  increasing  in  diameter 
with  the  increased  growth  of  the  shell  above  the  deflected  portion,  the 
increased  diameter  of  the  tube  about  equaling  the  increased  diameter 
of  the  whorl. 

Surface  of  the  shell  ornamented  by  low,  subangular,  transverse  ridges 
or  costa,  which  pass  entirely  around  the  shell  and  are  separated  by 
wider  concave  interspaces ;  also  by  two  longitudinal  rows  of  obliquely 
rounded  nodes,  the  upper  one  of  which  is  placed  at,  or  just  below,  the 
periphery,  and  the  other  at  about  one-eighth  of  the  circumference  of 
the  tube  below  the  first,  and  on  the  line  of  the  same  ridge  with  it. 
Transverse  costa  arranged  in  sets  of  three  5  two  of  each  set  coalescing 
to  form  the  oblique  nodes,  the  third  one  passing  around  the  tube,  without 
interruption,  midway  between  the  two  adjacent  pairs  of  nodes.  The 
direction  of  the  costa  is  strongly  backward  on  the  upper  inner  surface 
of  the  volution,  then  recurving  and  passing  obliquely  forward  in  cross- 
ing the  outer  face  of  the  shell  from  above  to  the  base,  and  also  within 
the  umbilicus.  Siphuncle  small,  marginal,  situated  as  far  above  the 
upper  line  of  nodes  as  the  distance  between  the  two  lines. 

Septa  approximate,  the  extremities  of  the  lobes  of  one  slightly  inter- 
fering with  those  of  the  saddles  of  the  next  adjacent,  but  not  interlock- 
ing ;  the  space  occupied  by  the  convolutions  of  the  lobes  and  sinuses  of 
a  septum  is  equal  to  three-fifths  of  the  diameter  of  the  tube  at  the 
position  of  the  septum  measured ;  the  ramifications  of  the  lobes  are 
sharply  angular  and  pointed.  The  siphonal  lobe  is  longer  than  wide,, 
deeply  divided  at  the  extremity  into  two  rather  long,  compound  digitate 
processes,  and  a  short  median  bifid  process.  First  lateral  lobe  very 
deeply  and  unequally  divided  and  the  branches  widely  spreading,, 
and  deeply  serrate-digitate.  Second  lateral  lobe  very  much  smaller  than 
the  first  and  less  spreading.  Antisiphonal  lobe  single,  longer  than  wide, 
deeply  digitate  on  the  side  and  divided  into  four  small,  unequal  digita- 
tions  at  the  extremity.  Sinuses  large,  spreading,  and  deeply  cleft  by 
auxiliary  or  secondary  lobes. 

The  type  specimen  of  the  species  is  imperfect,  but  preserves  one  and 
one-third  volutions ;  the  volutions  are  entirely  disconnected  and  increase 
rapidly  in  size,  while  the  umbilicus  retains  the  same  diameter,  the  upper 
volutions  appearing  to  have  been  not  more  closely  coiled  than  those 
preserved.  The  outer  extremity  of  the  specimen  retains  a  part  of  the 
deflected  portion  which  is  bent  downward  as  well  as  outward,  and  is 
septate  nearly  to  the  end.  The  species  appears  to  be  related  to  H.  f 
Nebracensis,  M.  &  H.,  Pal.  U.  S.  Geol.  Surv.  Territ.,  p.  480,  pi.  22,  fig.  1, 
a,  &,  o,  but  differs,  however,  in  the  more  rapidly  increasing  volutions  ; 
in  the  disconnected  whorls  ;  simple  costa  (i.  e.,  not  bifurcating) ;  in  the 
position  of  the  siphuncle,  and  in  the  details  of  the  lobes  and  sinuses. 

Formation  and  locality. — In  limestones  of  the  Fort  Pierre"  group,  on  the 
west  side  of  Beaver  Creek,  southwest  Black  Hills. 


42 


GENUS  ANCYLOCERAS,  D'0r&. 
ANCYLOCERAS  JENNEYI,  n.  sp. 

Plate  16,  figs.  6-8. 

Shell  ot  moderate  size,  composed  of  two  or  more(t)  rapidly-increasing 
volutions,  enrolled  on  the  same  plane,  and  entirely  disconnected ;  the 
inner  ones  apparently  leaving  a  broad,  open  umbilical  space.  Shell 
rather  rapidly  increasing  in  size  with  increased  age.  Volutions  slightly 
flattened,  on  the  back  vertically  compressed  and  transversely  oval  in 
section  j  the  vertical  diameter  being  only  about  two-thirds  as  great  as 
the  dorso-ventral  in  the  larger  part  of  the  shell,  the  greatest  height 
being  nearest  to  the  ventral  margin. 

Surface  of  the  shell  marked  by  strong,  distant,  transverse,  encircling 
ridges,  which  are  directed  slightly  forward  in  passing  from  the  dorsal  to 
the  ventral  margin,  and  in  crossing  the  latter  they  become  nearly  obso- 
lete. Occasional  intercalated  ridges  occur  at  irregular  distances  on  the 
dorsal  side.  Intercostal  spaces  concave.  The  shell  is  further  orna- 
mented by  two  lines  of  obtusely  rounded  nodes,  which  are  situated  on 
the  ribs  at  the  angles  of  the  flattened  dorsum. 

Septa  somewhat  complicated  and  closely  arranged,  sothat  the  inner 
lobes  interfere  with  the  extremities  of  the  sinuses  of  the  one  in  advance  but 
on  the  dorsal  portion  they  are  more  distant.  Siphonal  lobe  longer  than 
wide,  deeply  divided  at  the  extremity  and  terminating  in  two  large,  strong- 
ly serrated  digitatlons,  having  one  or  two  lateral  spurs  on  their  outer  side. 
First  lateral  lobe  large,  deeply  bipartite,  each  branch  terminating  in 
two  or  three  unequal  digitatious,  and  with  several  smaller  spurs  on  the 
sides  above.  Second  lateral  lobe  much  smaller  than  the  first,  deeply 
bipartite,  with  numerous  strong  spurs  irregularly  arranged  along  the 
margins.  Antisiphonal  lobe  long,  narrow  and  simple,  but  with  long 
lateral  serrated  spurs  and  a  slightly  tripartite  extremity.  First  and 
second  sinuosities  rather  large,  deeply  divided  by  large  auxiliary  lobes 
into  two  principal  branches,  which  are  again  deeply  divided.  Third 
sinus  smaller  than  the  others  and  divided  into  two  principal  branches. 
The  margins  of  all  lobes  and  sinuses  deeply  serrated. 

The  species  is  described  from  an  imperfect  individual,  and  a  second 
smaller  fragment  of  a  larger  specimen.  They  consist  only  of  the  con- 
volute parts,  and  show  no  evidence  of  the  deflection  of  the  tube.  It  is 
possible  they  are  not  rightly  referred  to  the  genus  Ancyloceras,  but  are 
more  nearly  related  to  the  genus  Anisoceras  of  Pictet,  which  differs 
from  the  former  genus  in  being  irregularly  helicoid.  The  example  fig- 
ured would  seem  to  have  been  somewhat  irregularly  coiled,  but  this 
may  possibly  be  the  effects  of  distortion,  as  the  smaller  coils  of  the  shell 
are  considerably  displaced.  It  differs  from  Ancyloceras  also,  as  defined 
by  Mr.  F.  B.  Meek  (Pal.  LT.  S.  Geol.  Surv.  Territ.,  p.  409),  iu  having 


43 

the  terminations  of  the  lobes  bipratite  instead  of  tripartite ;  but  this 
character  does  not  appear  to  hold  good  among  many  of  those  referred 
to  the  genus,  and  as  we  have  not  seen  the  septa  of  the  type  species  we 
are  uncertain  if  it  is  an  original  feature  of  the  genus  or  only  an  errone- 
ously added  one. 

Formation  and  locality. — In  limestone  referred  to  the  Fort  Pierre 
group  of  the  Upper  Missouri  Cretaceous,  on  the  East  Fork  of  Beaver 
Creek,  three  miles  west  of  Camp  Jenney,  Black  Hills. 

AXCYLOCERAS  TRICOSTATUS,  n.  8p. 

Plate  15,  fic?s.  7  and  8. 

A  single  fragment  of  a  sinistra,  helicoid  shell,  the  volutions  of 
which  have  been  entirely  separate  and  coiled  upon  the  same  plane,  with 
a  rapidly  increasing  curvature,  appears  to  possess  features  entirely  dis- 
tinct from  those  of  any  described  species.  The  form  of  the  volution  has 
been  quadrangularly  ovate  in  section,  vertically  compressed,  with  the 
greatest  vertical  thickness  at  about  the  inner  third  of  the  width,  and 
slightly  flattened  on  the  dorsum.  The  shell  is  marked  by  a  line  of 
strong,  angular  nodes  on  each  dorsal  angle,  and  by  closely  arranged, 
subangular,  encircling  ridges  or  costa,  which  are  directed  slightly  for- 
ward in  crossing  from  the  ventral  to  the  dorsal  margin  on  the  upper 
side  of  the  volution,  and  much  more  strongly  so  in  crossing  from  the 
upper  to  the  lower  side  of  the  dorsal  flattening,  and  are  recurved  below 
and  on  the  umbilical  surface.  The  costa  are  arranged  in  sets  of  three, 
the  two  adjacent  ones  of  which  unite  in  the  nodes  on  the  upper  and 
lower  dorsal  angles,  while  the  third  ridge  of  each  set  encircles  the  shell 
between  the  nodes  of  two  adjacent  sets.  Intercostal  spaces  concave. 

Septa  very  complicated  and  distant;  the  space  between  two  adjacent 
ones  equal  to  about  one-third  of  the  space  occupied  by  the  convolutions 
of  a  single  septum,  at  the  point  indicated.  The  dorsal  lobe  is  almost 
twice  as  long  as  wide,  deeply  divided  at  the  lower  extremity  by  a  broad 
tridentate  sinus,  each  division  being  again  divided  into  two  widely 
divergent,  dentate  branches.  There  are  also  two  lateral  dentate  spurs 
above  on  each  side  of  the  lobe.  First  lateral  lobe  large,  but  slender  > 
divided  into  two  principal  widely  divergent  branches,  each  of  which  is 
again  divided  and  furnished  with  several  strong  dentate  spurs  on  the 
margins;  two  other  spurs  of  similar  character  exist  on  each  side  of  the 
lobe,  one  just  below  the  bifurcation,  and  the  other  some  distance  above. 
Second  lateral  lobe  smaller  than  the  first,  deeply  divided,  with  the 
branches  less  divergent,  but  again  divided,  and  the  inner  branches  tri- 
furcate,  the  outer  branches  short  and  strongly  dentate.  Autisiphonal 
lobe  small  and  simple,  marked  by  one  small  spur  on  each  side  above, 
and  two  larger  curved  and  dentate  ones  below  ;  the  central  termination 
being  minutely  tridentate  at  its  extremity.  First  lateral  sinus  large, 
very  deeply  divided  into  two  principal  branches,  each  of  which  is 


44 

deeply  divided  above  and  strongly  lobed  on  the  sides.  Second  sinus 
smaller,  less  deeply  and  unequally  divided,  the  outer  half  smallest  and 
deeply  lobed,  the  other  less  deeply  so.  Antisiphonal  sinus  very  large 
(considering  the  parts  separated  by  the  antisiphonal  lobe  as  one  sinus), 
the  antisiphonal  lobe  dividing  it  nearly  to  the  base,  and  the  divisions 
again  very  deeply  divided  and  deeply  lobed  on  the  sides.  Siphuncle 
small,  situated  between  the  lines  of  nodes  and  marginal. 

This  species  differs  from  Ancyloceras  Jenneyi  in  being  sinistrally 
coiled,  and  in  the  character  of  the  ridges  of  the  surface  and  angular 
nodes.  We  know  of  no  other  species  described  with  which  it  is  enough 
related  to  require  a  comparison. 

Formation  and  locality. — In  limestone  at  the  top  of  the  Fort  Pierre 
group,  on  the  Cheyenne,  near  French  Creek,  Black  Hills,  Dakota. 

PTYCHOCERAS  MEEKANUM,  n.  sp. 

Plate  16,  figs.  1  and  2. 

Shell  of  small  size,  subcylindrical  or  vertically  compressed,  giving  a 
somewhat  oblate-transverse  section,  very  gradually  increasing  in  diam- 
eter with  the  increased  length  ;  smaller  limb  slender,  gently  curved  or 
bent  in  the  middle  of  its  length,  so  as  to  give  the  earlier  and  middle 
portions  of  the  shell  an  angle  of  about  135°  to  each  other.  Larger 
limb  or  outer  chamber  closely  appressed  and  slightly  embracing  the 
smaller,  and  extending  to  near  the  middle  of  the  curvature. 

Surface  of  the  entire  shell  marked  by  strong,  simple,  sharply  angular, 
oblique,  encircling  ridges,  with  wider,  deeply  concave  interspaces,  very 
regularly  increasing  in  distance  from  the  apex  outward,  and  on  the 
dorsal  region  by  two  longitudinal  rows  of  spines  or  spiniform  tubercles, 
situated  at  about  or  nearly  one-sixth  of  the  circumference  of  the  tube 
from  each  other,  and  on  the  crests  of  the  ridges.  The  encircling  ridges 
are  directed  obliquely  forward  in  passing  from  the  ventral  to  the  dorsal 
surface  in  the  smaller  limb,  but  have  the  opposite  direction  on  the 
larger ;  space  between  the  lines  of  nodes  very  gently  concave. 

Septa  approximate,  but  more  distant  than  the  surface-ridges  of  the 
shell,  deeply  lobed,  and  the  lobes  and  sinuses  somewhat  complicated. 
The  dorsal  or  siphonal  lobes  are  nearly  as  wide  as  long,  broadly  forked 
at  the  extremity,  and  the  outer  side  of  the  forks  marked  by  several 
short  rounded  digitations.  First  lateral  lobe  divided  into  two  diverging 
branches,  with  lobed  margins.  Second  lateral  lobe  narrower  and  more 
slender  than  the  first,  and  more  deeply  forked ;  the  division  being 
marked  by  short  rounded  digitations.  Ventral  or  autisiphonal  lobe 
small,  but  deeply  forked,  and  the  margins  sinuous.  Sinuses  nearly 
equal  in  size,  each  of  them  deeply  divided  in  the  middle  by  an  auxiliary 
lobe ;  slightly  bifid  in  the  first  and  second  but  simple  in  the  third  ; 
division  of  the  sinuses  marked  by  short  rounded  digitations.  Siphon 
of  moderate  size,  marginal,  and  placed  between  the  lines  of  nodes. 


45 

Before  entering  upon  a  critical  study  of  the  specimens  before  us,  we 
bad  supposed  them  to  be  identical  with  Ptychoceras  Mortoni  M.  &  H., 
and  hesitated  to  consider  them  as  distinct ;  but  there  are  so  many 
points  of  difference,  and  the  variations  are  so  great,  that  it  appears  im- 
possible to  avoid  this  conclusion,  and  equally  difficult  to  unite  the  two 
forms  here  mentioned.  More  especially  is  this  the  case  if  any  reliance 
is  to  be  placed  on  the  structure  and  location  of  the  septa.  We  are  quite 
well  aware  that  this  latter  feature  is  one  liable  to  great  variation,  de- 
pendant upon  the  growth  of  the  individual ;  but  the  lobations  in  the 
septa  at  the  smaller  extremity  of  the  specimen  figured  is  much  more 
complicated  than  that  shown  by  Mr.  Meek,  to  exist  in  the  type  specimen 
of  P.  Mortoni.  Beside  the  difference  in  the  septa,  the  form  of  the  tube 
varies  in  being  wider  than  high,  the  reverse  of  that  species,  and  the 
antisiphonal  surface  of  the  tube  is  always  flattened,  and  the  costa 
always  simple. 

Formation  and  locality.— In  limestone  of  the  Fort  Pierre"  group,  oil 
Beaver  Creek.  Black  Hills. 

PTYCHOCERAS  CRASSUM,  n.  sp. 

Plate  16,  figs.  3-5. 

Entire  form  of  shell  unknown.  The  portion  preserved  is  rather  robust 
in  habit  and  the  shell  much  thickened,  except  on  the  ventral  surfaces. 
Transverse  section  subcyliudrical  or  slightly  compressed  in  a  dorso- ven- 
tral direction,  the  larger  limb  being  concave  on  the  ventral  side  and 
slightly  embracing  the  smaller  part.  Tube  regularly  increasing  in 
diameter  with  increased  growth.  Shell  ornamented  by  strong,  sharply 
angular,  encircling  ridges,  which  are  directed  forward  in  passing  from 
the  ventral  to  the  dorsal  sides  of  the  smaller  limb,  but  have  the  oppo- 
site direction  on  the  larger  part;  also  by  two  longitudinal  lines  of 
pointed  nodes  or  spines  on  the  dorsum,  which  are  separated  by  a 
moderately  wide,  slightly  concave  space. 

Septa  distant,  one  septum  nearly  equaling  two  of  the  transverse 
ridges,  except  near  the  bending  of  the  tube  where  there  are  two  o£  the 
septa  placed  nearer  to  each  other,  beyond  which  the  shell  is  not  sep- 
tate. Lobes  and  sinuses  of  the  septa  somewhat  complicated;  the 
siphonal  lobe  longer  than  wide,  and  broadly  forked  at  the  extremity. 
First  lateral  lobe  large,  divided  into  two  principal  branches,  the  outer 
one  being  again  deeply  divided,  and  the  margins  of  the  branches  serrato- 
digitate.  Second  lateral  lobe  smaller  than  the  first,  divided  into  three 
short  serrate  digitations.  Antisiphonal  lobe  small  and  simple,  marked 
only  by  two  short  digitations  on  each  side.  First  and  second  sinuses 
much  larger  and  broader  than  the  lobes,  deeply  divided  in  the  middle 
by  a  small  serrated  auxiliary  lobe,  and  the  divisions  each  again  divided 
and  serrate.  Antisiphonal  sinus  a  little  smaller  than  the  others,  but 
more  deeply  divided  by  the  antisiphonal  lobe,  and  the  branches  again 


46 

deeply  divided.  All  the  margins  of  the  lobes  and  sinuses  are  charac- 
terized by  small,  rounded  serrations.  Siphuucle  of  moderate  size,  mar- 
ginal and  situated  between  the  lines  of  nodes. 

The  distinction  between  this  and  the  preceding  species  consists  in 
its  large  size,  more  robust  habit,  and  thicker  shell,  and  in  the  more 
distant  and  much  more  complicated  septa.  It  is  still  further  removed 
by  these  characters  from  P.  Mortoni  M.  &  H.,  as  well  as  by  the  simple 
ridges. 

Formation  and  locality. — In  limestone  of  the  Fort  Pierre  group,  on  Old 
Woman's  Fork,  Black  Hills. 


LIST   OF   FOSSILS   DESCRIBED   IN   THE    KEPOKT   OF   THE 
PALEONTOLOGY  OF  THE  BLACK  HILLS. 

POTSDAM  GROUP. 


Name. 


Locality. 


Palseochorda  prima,  D.  sp 

Pal  reopb  yens  occidentals,  D.  sp, 
sp,  uudet 


INCERTECEDES. 


Scolitnus,  sp. 


BRACHIOPODA. 


Lingulepis  piunaformis,  Owen 

cuueolus,  n.  sp 

perattenuatus,  n.  sp 

Dakotensis,  Meek  &  Hayden 

Obolus  ?  pectenoides,  Whitf 

Obolella  polita,  Hall 

Obolella  naua,  M.  &  H 


CRUSTACEA. 


Crepicephalus  (Loganellns)  centralis,  n.  sp. 
planus,  n.  sp  .. 


Head  of  Red  Water  Valley. 
Do. 
Do. 


Warren's  Peak. 


Red  Canon  Creek. 

Do. 

Do. 
Castle  Creek. 

Do. 
Red  Water  Canon. 

Do. 


Castle  Creek. 
Do. 


JURASSIC. 


RAD  I  AT  A. 


Asterias?  dnbium,  n.  sp 

Pentacrinus  asteriscus,  M.  &  H. 


BRACHIOPODA. 


Lingula  brevirostris,  M.  &  H... 
Rbynchonella  inyrina,  H.  &.  W 


Spear's  Fork  of  Red  Water  Creek. 
Big  Horn  Mountains. 


Spear's  Fork  of  Red  Water  Creek. 
Red  Canon  Creek, 


47 


List  of  Fossils  j  &c. — Continued. 
JURASSIC. 


Name. 


LAMELLIBRANCHIATA. 


Locality. 


Ostrea  strigilecula,  White Belle  Fonrcbe,    Sun-Dance   Hills, 

and  near  Beaver  Creek. 

Gryphsea  calceola  var.  Nebracensis,  M.  &  H j  Big  Horn  Mountains. 

Pecten  Newberryi,  n.  sp 

Camptonectes  bellistriata,  Meek !  Belle  Fourche. 

extenuatus,  M.  &  H i  East  of  Belle  Fourcbe. 

Pseudomonotis  (Eumicrotis)  curta,  Hall !  Two  miles  south  of  Belle  Fouicbe, 

orbiculata,  n.  sp Red  Water  Valley. 

Avicula  (Oxytoma)  mucronata,  M.  &  H Two  miles  south  of  Belle  Fourche. 

Ger villia  recta,  Meek  in  MS Sun-Dance  Hills. 

Grammatodon  inornatus,  M.  &  H 

Mytilus  White!,  n.  sp j  Sun-Dance  Hills. 

Volsella  (Modiola)  formosa,  M.  &  H i  Big  Horn  Mountains. 

pertennis,  M.  &  H |  (September  20.) 

Astarte  fragilis,  M.  &  H |  Red  Water  Valley. 

Trapezium  bellefourchensis,  n.  sp j  East  of  Belle  Fourche. 

subequalis,  n.  sp j  Red  Canon  Creek. 

Pleuromya  Newtoni,  n.  sp j  Two  miles  south  of  Belle  Fourche. 

Tancredia  ( ?)  inornata,  M.  &  H East  of  Belle  Fourche. 

corbuliformis,  n.  sp Do. 

bulbosa,  n.  sp Do. 

postica,  n.sp Do. 

Warreuana,  M.  &  H I  Red  Water  Valley. 

Dosinia  Jurassica,  n.  sp j  East  of  Belle  Fourche,  &c. 

Psammobia  (?)  prematura,  n.sp j  Do. 

Thracia  snblevis,  M.  &  H Red  Water  Valley. 

Neaera  longirostra,  n.sp Do. 

Saxicava  Jurassica,  n.  sp Do. 

CEPHALOPODA. 

Ammonites  cordiformis,  M.  &  H !  Red  Water  Valley. 

var.  distans |  Two  miles  south  of  Belle  Fourche. 

Belemnites  densus,  M.  &H East  of  Belle  Fourche. 


CRETACEOUS. 


Systematic  name. 


Division. 


Locality. 


LAMELLIBRAXCHIATA. 

Cyncyclonema  rigida.  M.  &  H 

Pteria  linguiformis,  Evans  &  Shurn. .. 

(Oxytoma)  Xebrascana,  E.  &  S. 
(Pseudopteria)  tibrosa,  M.  &H. 

sublse  vis,  n.sp.. 
Inoceramus  problematicns,  Schlott... 

fragilis,  H.  &  M 

altus,  Meek 

perplexus,  n.  sp 

sublsevis,  H.  &  M 

Sagensis,  Owen 


No.  4. 
No.  4. 

No.  4. 
No.  4. 


No.  4 

Nos.2and3. 
Nos.  2  and  3. 
No.  2 

No.  2 

No.  4. . 

No.  4.. 


Forks  of  the  Cheyenne  River. 
Chevenne    River,  near    French 

Creek,  &c. 
Sage  Creek. 
Cheyenne     River,    near     Rapid 

Creek. 

Old  Woman's  Fork. 
East  Fork  of  Beaver  Creek. 
Beaver  Creek. 
Belle  Fourche,  10  miles  west  of 

Crow  Creek. 
Belle  Fourche,  10  miles  west  of 

Crow  Creek. 
Forks  of  the  Cheyenne  River. 


48 


List  of  Fossils,  &c. — Continued. 
CRETACEOUS. 


Systematic  name. 


LAMELLIBRANCHIATA — Continued. 

Inoceramus  Simpsoni,  Meek 

Vanuxemi,  M.  &  H 

var. ., 


Barabini,  Morton 


tenuilineatus,  M.  &  H  . . . 
Endocostea  typica,  u.  sp 

sulcata,  Roemer 

Idonearca  Shuinardi,  M.  &  H 

Nucula  planimarginata,  M.  &  H | 

Nuculana  bisulcata,  M.  &  H 


Division. 


Locality 


subequilatera,  n.  sp 


YoldiaEvansi,  M.  &.H 

Lucina  occidentals,  Morton 


ventricosa,  H.  &  M 

(Diplodonta)subundata,H.&M. 

Crassatella  subquadrata,  n.  sp 

Astarte  Evansi,  H.  &M 

Veniella  humilis,  M.  &  H 

Sphaeriola  transversa,  n.  sp 

Dosinia  Missouriana,  Morton 

Thetis  circularis,  M.  &  H 

Leiopistha  (Cymella)  Meeki,  n.  sp 

Thracia  subgracilis,  n.  sp 

Nesera  Moreauensis,  M.  &  H  ? 

GASTEROPODA. 

Fasciolaria  (Cryptorbytis)  fusiformis, 

H.  &  M. 

Fasciolaria  (Cryptorhytis)  contorta,  M. 
(Piestocbeilus)   Culbert- 
soui,  M.  &  H. 

Fasus  Shumardi,  H.  &  M 

Cheyennensis,  n.  sp 

Aporrbais  Newberryi,  Meek 

Meeki,  n.sp 

(Goniocbeilus)  Castorensis, 
n.  sp. 

Ancliura  ?  sublaevis,  M.  &  H 

CDrepanocheilus)  Nebracen- 

sis,E.&S 

Lunatia  concinna,  H.  &.  W 

Vanikora  ambigua,  M.  &  H 


No.  4 

No.  4 

No.  4 

No.  4.. 

No.  4 

Nos.  4  and  5. 
N  os.  4  and  5. 
No.  5....... 

No.  4 

Nos.  4  and  5. 

No.  4 

No.  4  or  5.. 


Nos.  4  and  5 
No.  4 

No.  4.. 


No.  4? 

No.  4 

No.  5 , 

No.  5 

No.  4.... 
No.  4 

No.  5 

No.  4 

No.  4.. 


No.  4 


No.  4  or  5... 
No.  4  or  5... 

No.  2 

No.  4. 

No.  5 

No.  4 

No.  4  or  5... 

No.  4 

No.  4  or  5... 

No.  4 

No.  4.. 


!  Old  Woman's  Fork. 

Do. 
Belle  Fourche,  10  miles  west  of 

Crow  Creek. 

Cbeyenne  River,  near  Box  Elder 
Creek. 

Old  Woman's  Fork. 

Loose  on  Beaver  Creek. 

Cbeyenne  River,  near  Old  Wo- 
man's Fork. 

Cbeyeune  River,  (May  31.) 

Cbeyenne  River,  near' Box  Elder 
Creek. 

Cbeyenue  River,  near  French 
Creek. 

Old  Woman's  Fork,  &c. 

Cbeyenne  River,  near  Rapid 
Creek. 

Cbeyenne  River,  near  Rapid 
Creek. 

Cbeyenne  River,  near  Rapid 
Creek. 

Cheyenne  River. 

Cbeyenne  River,  near  Rapid 
Creek. 

Cbeyenne  River,  near  Old  Wo- 
man's Fork. 

Cheyenne  River,  near  Old  Wo- 
man's Fork. 

Cheyenne  River. 

Cheyenne  River,  near  Rapid 
Creek. 

Dead  Man's  Rapids,  Upper  Mis- 
souri. 

Cheyenne  River,  near  Rapid 
Creek. 

Forks  of  the  Chevenne  River. 


Cbeyenne     River,    near     Rapid 

Creek. 

Old  Woman's  Fork. 
Near  French  Creek. 

East  Fork  of  Beaver  Creek. 
Cheyenne     River,    near     Rapid 

Creek. 

Rio  de  la  Plata. 
Cheyenne     River,    near     Rapid 

Creek. 
East  Fork  of  Beaver  Creek. 

Near  Box  Elder  Creek. 
East  Fork  of  Beaver  Creek. 

Cheyenne     River,    near    Rapid 

Creek. 
Cheyenne  River. 


49 


List  of  Fossils,  &c. — Continued. 
CRETACEOUS. 


Systematic  name. 

Division. 

Locality. 

GASTEROPODA—  Continued. 
Amauropsis  paludinaeformis,  H.  &M.. 
Margarita  Nebracensis,  M.  &  H  

Anisomyon  alveolus,  M.  &  H  
subovatus,  M.  &H  

patelliformis  M  &  H 

No.  4  
No.  4  

No.  4  
No.  4  

No.  4.  ... 

Cheyenne  River,  near  Box  Elder 
Creek. 
150  miles  above  mouth  of  Yellow- 
stone. 
Old  Woman's  Fork. 
Do. 
Do. 

borealis  Morton 

No  4 

Cheyenne  River. 

Akera  glans-oryza  n  sp 

No.  4  

Chevenne    River,   near    French 

Haminea  subcylindrica,  M.  &  H  

No.  4  
No.  4  

Creek. 
Old  Woman's  Fork. 
Cheyenne     River,   near    Rapid 

CEPHALOPODA. 

Nautilus  Dekavi  var  Montanensis  M 

No.  4  

Creek. 
Cheyenne    River     near     Rapid 

Prionocyclus  Wyomingensis,  Meek  
Scaphites  nodosus  Owen      .  

No.  2  
No.  4  

Creek. 
Chevenne     River,   near     Rapid 

var.  brevis,  Meek  .  . 

quadran  gu- 
laris   Meek 

No.  4  

No  4 

Creek. 
Cheyenne     River,    near    Rapid 
Creek. 

Cheyenne     River,    near     Rapid 

plenus  M  &  IT 

No.  4  .  .  . 

Creek. 

Warreni,  M.  &  H  
Wyomingensis,  M.  &  H  
Helicoceras  Stevensoni,  n.  sp  
Heteroceras  Newtoni,  n.  sp  
?  Nebracensis,  M.  &  H  .  .  . 
Ancycloceras  Jenneyi,  n.  sp  
tricostatum,  n.  sp  

Ptychoceras  Meekanum,  n.  sp  
erassuin,  n.  sp  

No.  2  
No.  2  
No.  4  
No.  4  
No.  4  or  5... 
No.  4  
No.  4  

No.  4.. 
No.  4  

East  Fork  of  Beaver  Creek. 
Do. 
West  of  Beaver  Creek. 
Do. 
East  Fork  of  Beaver  Creek. 
Do. 
Cheyenne    River,  near    French 
Creek. 
Beaver  Creek. 
Old  Woman's  Fork. 

4  B  H 


.   O 


YC  36318 


